This depends strongly on your DM's personality.
Remember, everyone is playing tabletop games to have fun together, so if something is happening to dampen your fun, it's completely reasonable to bring that up, but keep in mind you don't want to ruin the DM's/everyone else's fun while you're at it. It sounds like you understand this ("I don't want to be ...
As somebody who is mostly GM'ing, here's how I'd feel about what kind of feedback:
"I really enjoyed that specific part because XXX"
"I prefer having a bit more roleplay, for example..."
"I like strategy in battles, would be nice if we could use maps / strict turn-taking more often"
These are all for before or after ...
Communication is key
It highly depends on how sensitive a particular person reacts to critique, but as a DM (for 20 years) I always hope that my players give me feedback if they have fun or not... or if I get some rules horribly wrong. I know that not all DMs think that way tho. But you know him or her better than me and can maybe estimate a possible ...
Engage with your DM about Feedback
Personally I believe that all DM's should be open to feedback. Ultimately how much our players are enjoying the game is the only metric that measures how 'good' we are as a DM. If the players can't communicate what they are enjoying/not enjoying with the DM how can they improve?
In your situation I would recommend ...
Official rules lawyer here. From my experience, as long as you're respectful and acknowledge that the GM has final say, no one really gets mad when you try to help with rules clarifications. Before you attack, you might say "Alright, I'll roll for initiative." It's a leading statement, but the table should get the hint.
Be kind, be respectful, but ...
If something is causing you to not have fun, you can tell the DM: "Hey, this thing is causing me to not have fun, can we do it differently?"
If I were playing at your table, I can tell you that two of the things you describe would cause me to not have fun, and the rest would seem sort of eccentric but irrelevant. I would say:
"Hey, in that ...
An answer of a new GM
This answer is my take on it and you should choose which points are suitable for you.
Make sure the fun continues
The game should be fun for GM but mostly the players.
If the GM creates a lot of situations that only allow 1 player to play while the other are bored you need to point that out and ask for some balance. It can happen that ...
Let's compare your custom model to the others...
Guardian (Special Weapon(s): Thunder Gauntlets)
two simple melee weapons (not light) that deal 1d8 thunder damage
A creature hit by the gauntlet has disadvantage on attack rolls
against targets other than you until the start of your next turn
As a bonus action, you can gain temporary hit points equal to your ...
You have a few problems
Replacing all ability checks with a single stat seriously overpowers a class.
INT instead of STR for ability checks.
This is horribly broken; consider "Intelligence instead of Strength for athletics checks" instead.
Charge is mess.
First you need to define what it is: is it an action, a bonus action, what?
You also have ...