I tried searching for this answer but found unfavorable answers, however, they were pretty old discussions. Does it currently work well with Heroic launcher?

I think it's still in beta but the option is available if you want to try it but backup your saves before using it to be sure to not lose your saves

Tried it yesterday, for some games it works, for others it doesn't.

In particular I tried A Plague Tale Innocence and Requiem where I was able to download my Galaxy cloud saves just fine.

On the other hand, I didn't have success downloading cloud saves for Falcom titles. it seems like it recognizes the files on the server but doesn't download them (Tried Trails in the Sky FC and Ys: The Oath in Felghana).