Sentient AIs seem to be a lot less common and less powerful computationally in Fed space than in the Culture.

Lore/Data/Lal, Moriarty, the Doctor and that’s pretty much it.

V’Ger is earlier, but was overclocked by unknown alien technology, and therefore not replicable by the Feds.

Although a starship computer of the TNG era, i.e. the latter third of the 24th Century, has enough computing power to create a sentient AI, Moriarty, by what is essentially a mistake in Data’s vibe coding, there seems to be some kind of brake to keep starship computers from becoming sentient themselves.

Culture AIs come in a huge range of capabilities from GSV commanding Minds to drones like Mawhrin-Skel with about the same level of intelligence as the biological citizens, to a sentient survival suit.

If you read closely, although the meatbag characters largely take center stage, it’s the GSV Minds who directly control the vast majority of resources, come to consensus among themselves on strategy, or go loose cannon, or sulk in a corner, and everyone else is literally just along for the ride.

Nor really.

The Feds still have meatbags making decisions.

The Culture humanoids are “lucky” enough to have benevolent AIs who spoil them like pets.

Less benevolent AI rule might look like Saberhagen’s Berserkers, or Battlestar Galactica’s Cylons.

I know you didn’t ask, but:

As weird as it sounds, I don’t think the Borg are ruled by AI. If they were, they’d be a lot scarier than they already are. Cyborg meat brains, e.g. the Borg Queen, are still in charge of making stupid decisions.

Some people would want those!

Octopi. They’re freakishy intelligent too.

How about something like The Culture?

Highly advanced multi-species civilization ruled by benevolent AIs?

I have a nagging feeling that something like it should have appeared in Trek at some point.