Yes, it is particularly underwhelming.
Suppose your table actually runs what the Dungeon Master's Guide calls The Adventuring Day:
Assuming typical adventuring conditions and average luck, most adventuring parties can handle about six to eight medium or hard encounters in a day.
Our day will consist of two encounters, a short rest, three encounters, a ...
Avoid "all or nothing" spells, especially against boss type enemies.
By "all or nothing", I'm referring to spells, like Disintegrate, that have zero effect on a creature that saves against them. These spells are especially risky against bosses that tend to have high saving throws and/or Magic Resistance, and may have Legendary ...
It's useless, if you mainly use Inspiration in combat
This might seem like a strange statement, since Superior Inspiration triggers upon entering combat, but it's important to keep in mind how this changes out-of-combat use. A 20th level bard can expend all the inspiration they want avoiding a fight, or trying to work their way through a social encounter ...
We can do 360’ with a few magic items and guardian of nature.
Attunement free magic items: +60'
Goggles of night (does not require attunement):
While wearing these dark lenses, you have darkvision out to a range of 60 feet. If you already have darkvision, wearing the goggles increases its range by 60 feet.
Magic items requiring attunement: +180'.
Distant Animal Shapes: ~57 905
Our character is a Druid 15/Sorcerer 3 for animal shapes and the Distant Spell Metamagic respectively.
Animal shapes lets us transform any number of willing creatures within range into spiders:
Choose any number of willing creatures that you can see within range. You transform each target into the form of a Large or smaller ...
You can get up to 36 spells under these conditions
In your own answer you have already found all the feats (as far as I could also find) that provide extra spells known with charisma, for a total of 5, so only for completeness, they are Magic Initiate, Fey Touched and Shadow Touched from this unearthed arcana (pdf).
Focusing on spells from classes, though, ...
The bard's capstone ability is extremely underwhelming
I agree with the other answers that, certainly in combat (and given that D&D is a combat heavy game, not that is has to be, but it typically is and that mindset has informed its design), Superior Inspiration is extremely underwhelming. I can also confirm that there are no bard-specific magic items ...
I won't build the entire character for you, but I can make a couple of recommendations to improve the druid to excel at what you are wanting to do.
The standard druid spell list will have you mostly covered, but since your DM is permitting small borrowing from other spell lists, I would recommend suggesting your DM allow you to take some of the following ...
Depends on the Save
There are very few ways to automatically ensure a target fails a save. There are more options for increasing the likelihood of failure. But you should be aware that there is no counter to Legendary Resistances short of forcing them to be burnt through. Save or die is pretty much non-existent in 5e and Legendary Resistance is there to ...
Virtually no limit
If you are a level 17 wizard, with the simulacrum, wish, and polymorph spell can have any number of spiders.
By using wish to create simulacra, as detailed in this answer to a different Q&A, you can have essentially unlimited versions of yourself. Have each simulacrum cast polymorph to become a spider of choice, and you are all set.
The core druid spells ought to have you covered for this.
By level five you could take:
Shillelagh / Produce Flame / Primal Savagery
Wind Wall or Wall of Water
Call Lightening or Protection from Energy
The break even formula for GWM/SS requires a bit of algebra. First, our variables:
\$DAM\$ is average damage per hit before GWM/SS.
\$HIT\$ is bonus to hit before GWM/SS.
\$AC\$ is target armor class.
This is all we need to get our formula. We will set expected damage without GWM/SS equal to expected damage with it, and then solve for \$AC\$.
In this ...
A total of 36 Spiders
As an attempt at answering this myself, here's what I've come up with:
Druid 5 for Wild Shape and conjure animals;
Ranger 3 for a companion via Beast Master;
Lore Bard 6 for find familiar and find steed;
Remaining levels in any full caster class for a 9th level spell slot;
32 spiders summoned via conjure animals (if cast ...
A creature can have Mass Polymorph cast on them to gain 157-247 temporary hit points
Each target assumes a beast form of your choice, and you can choose the same form or different ones for each target. The new form can be any beast you have seen whose challenge rating is equal to or less than the target's (or half the target's level, if the target doesn't ...
The feat Rage Casting (Dragon #310 30) has stiff prerequisites: It requires 5 ranks in the skill Concentration; both the feats Combat Casting and Quicken Spell (Player's Handbook 92 and 98, respectively); the ability frenzy or rage; and the ability to cast 1st-level spells. The feat has the following benefit:
When raging, you can cast spells that you can ...
Be an Elf
The Elf race has a bunch of "bonus feats", though they are probably not that useful to your character:
Weapon Proficiency: Elves receive the Martial Weapon Proficiency feats for the longsword, rapier, longbow (including composite longbow), and shortbow (including composite shortbow) as bonus feats.
A total of 30 spells known that can be cast with spell slots using Charisma as the spellcasting ability
In my attempt to answer this, I've come up with the following:
A character with no more than 18 in Charisma; race is irrelevant;
Classes include Bard 7, Warlock 2, Sorcerer 11;
Feats include Magic Initiate, Fey Touched and Shadow Touched (the latter two ...
Average 414.5, Max 678; with a variant rule, average 512, max 858.
Class and Equipment
5 Whispers Bard: 3d6 psychic blades
2 Paladin: Divine Smite
9 Hexblade Warlock: 9 gets a 5th level pact slot for Eldritch Smite.
3 Fighter: For Action Surge, Battle Master.
1 Wizard: to have time stop on our spell list.
Feat: Great Weapon Master
Seeing farther than 120 feet requires stacking different bonuses
Getting more than 120 feet of darkvision is difficult. If you had started as a dark elf it would be easy using goggles of night.
Other possibilities would be using shadow sorcerer / gloom stalker, and goggles of night. Otherwise, you have to stack magic items.
Goggles of Night and ...
The question permits both Epic Boons and mass-simulacra duplication with the stipulation you've already made all the simulacra you can make. Since there is, in fact, no real limit on how many simulacra you might have (note you can make them exponentially faster with an Epic Boon), we start the round with an infinite number of simulacra. Our ...
No, GFB only triggers once
Greenflame blade description says
As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, ...
"On a hit" refers to the attack made as part of casting the spell, and the effect only applies to the spell's ...
Class level: Artificer 20
Artificers at high level have 6 atunment slots and the only rules preventing people using multiple copies of a magic item are exclusive to Adventurers League
Total Walking around Armor Class : 37 (only aplicable in game if you are suprised or out of spell slots)
18 Armor(Half Plate, +3)
+3 Dex bonus (Medium armor ...
If you take 3 levels of sorcerer, you can impose disadvantage on a save by spending 3 sorcery points. You can regain these points for a 3rd level spell slot, so you can use this quite a few times per day.
Otto's Irresistible Dance
This spell has an effect with no save allowed. The creature can then take an action on their next turn to try ...
I'd take two levels in Druid and two levels in Rogue
Two levels in Rogue gives you an ASI, Uncanny Dodge, and an increase in sneak damage. Two level in Druid gives you another ASI, a cantrip and access to 3rd level spells plus more spell slots.
So, Uncanny Dodge lets you halve the damage of an incoming attack using your reaction, which will help with ...
Cribbing heavily from my answer on the previous question, but if it ain't broke... (Goal is to maximise average damage on a weapon attack, without Time Stop/Wish shenanigans)
Average 254.5, max 345
Let's go for a goblin Tempest Cleric 9/Whispers Bard 7/Fighter 2/Paladin 2, casting Booming Blade with a Holy Avenger greatsword, fighting an undead creature. '...
401 Max Damage,
248 Avg Damage
Race: Scourge Assimar, Radiant Consumption +20
Feat: Great Weapon master +10
Skill: Poisoners Kit
Ring of 3 Wishes
Ioun Stone of Mastery +1 proficiency bonus
Scroll of time stop
Scroll of Staggering Smite 4d6
Scroll of Blinding Smite 3d8
Flame Tongue Great axe 1d12, +2d6 (+1 improved pact weapon)
Belt of storm giant strength +...
It seems there is nothing better than pit fighting (that is simple and direct)
Excluded: Crime, Gambling
Do not make money: Buying a magic item, carousing, crafting an item, relaxation, religious service, research, scribing a spell scroll, training
Pit fighting: The best simple option, like you already found but with a slight risk.
Selling a magic item: Can ...
Although you've mentioned in your question that you've already picked the Bladesinger subclass, for others looking for answers who do not have that restriction (i.e. the restriction of having already chosen their subclass):
Be a School of Divination wizard
As a School of Divination wizard, you have access to the Portent class feature (PHB, p. 116):
Many sites list “extremely powerful” builds, often with few if any entries that actually reach well into the limits of D&D 3.5e’s potential. Ultimately, there is a build that can have every stat as high as they choose to make it, and every ability in the game they choose to have, at 1st level—that would be Pun-Pun, and nothing is ever going to beat that ...