Just looking for game recommendations, though I do have a few constraints:
* The game must be one that I have already played before. (I'm not looking for something new.)
* I must be able to easily acquire and play the game if I don't already have it.
* The game must not be one I've been vocal about disliking. (So no Baldur's Gate 1/2, Ultima 7, or Final Fantasy 7, for example.)

So, any suggestions?

The point of recommendations usually is to learn about something one wouldn't have known about otherwise or at least was undecided about...limiting your request to games you've already played defeats the point of recommendations (and how is one supposed to know which games you've already played?). This feels like a troll post tbh.

Play all Final Fantasy Tactics games, and afterwards, tell us how the series evolved and if the games still hold up.

Except that I've only played the first one, and not either GBA or DS games. (I do own the GBA version on cartridge, but haven't actually played it.)

Well you want your next game to be something you already played, and after that you can start something new.

Sid Meier's Alpha Centauri. Enjoy!

Anachronox
Blade of Darkness
Wizardry 8
Divine Divinity
Wasteland 2 or 3

I have no idea what you have already played, but if you haven't played any of those, you should :)

Only one of these I've played is Wizardry 8.

Maybe I should replay Wasteland 1 (the only game in the series I've played, and the only one that actually interests me)?

You could try the Wasteland Remastered (made by Krome) Opinions are mixed and I have not tried it yet but the recently implemented macros from original, so that is a step in right direction for sure.
Edit:
Only if you have the game already in your library.

Dragon Age.

No clue what games you have or have played before. So i'll just give a few of my favorites.

Ring Runner
WindForge (which isn't on the store here anymore)
Rebel Galaxy
Neir Automata
TIS-100
Unmechanical

Wasteland 3, just for an excuse to tell people to play Wasteland 3

No idea what games you play, so replay Star Control 2 please.

I've never played that one, I might give the remaster a shot after I finish 3.
Yeah, I'm really enjoying it, great Fallout vibe.

I'm thinking of maybe playing the "The Original Classic" version, actually, and maybe using a hex editor to test some things.