I’m the same way regarding quirks. I’ve been using Gboard and for a while bounced between that and Samsung Keyboard. Gboard has the best overall usability for me but a couple things I’m not a fan of: Gboard deleting clipboard history (only from Gboard as it’s still available elsewhere), and including \ as a long press symbol rather than /,where you have to tsp the symbols key and then tap /.

Samsung Keyboard has a few quirks as well, but the biggest was predictive text isn’t as good as Gboard. But I like the customization of it. But I can’t see the symbols on the keys as well as I can on Gboard.

I was a fan of Chroma Keyboard years ago because I liked that it would change color based on the app.