How does my homebrew spell replacement for the Shadow Magic sorcerer's Hound of Ill Omen feature compare to the original?

Question

We are starting a new campaign soon with 7 players. To avoid a lot of extra rolling and stuff, the DM banned summons (companions/mounts).

I still wanted to play a Shadow Magic sorcerer (XGtE, p. 50-51) - but since the 6th-level feature, Hound of Ill Omen, is a summoned creature, I asked if I could homebrew something to replace it.

I tried my best to get a lot of aspects of Hound of Ill Omen in this replacement feature, but I wonder how it holds up against it. Is it stronger than Hound of Ill Omen, or weaker?

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My homebrew replacement feature is:

Shadow Link

1 bonus action

3 sorcery points

120 feet range

A line of shadow forms between you and the linked target. At the beginning of its turn, the linked target makes a Charisma saving throw. On a failed save, the target takes an amount of necrotic damage equal to your sorcerer level plus your Charisma modifier, and the following effects apply until the beginning of its next turn:

• You know where the target is, except if the target is invisible or on another plane.

• If the target moves more than half its speed, it takes an amount of necrotic damage equal to your sorcerer level, and has disadvantage on saving throws against any spell you cast.

The target can attempt to break the link by making a Charisma saving throw after the initial effect. The link also breaks if the target dies, or after 1 minute has passed.

Answer 1

The hound is going to average around 6 HP per round (or 8 HP if they have an ally to give them advantage on attacks) against an AC 15 target.

Sorcery level + CHA modifier is going to be at least 10 pts - Assuming a DC 15 saving throw that yields about 7 HP of damage per round.

Slight edge to the spell in damage output, unless the spell doesn't do damage every round in which case the hound is the clear winner

The hound can be killed, but that'd require the target (or it's allies) to spend attacks against it.

The spell can be broken, and here your wording is a bit confusing.

Does the target save round by round to prevent damage, but can also save to end the effect? Do they have to spend an action on the 'break the spell'save? Then again, allies can't help the target (except through dispel magic)

Slight edge to the hound in annoyance

The hound has knockdown.

The spell has the movement penalities.

About even

It seems pretty equivalent in terms of game effects, if anything it's a bit underpowered. If I was your DM, I'd allow it!

Really the only concern is how much better it becomes at higher levels. The hound doesn't improve at higher levels, whereas your spell could be cranking out an average of 20 damage a round at high levels.