The state of OSS keyboards is lamentable - no shade to devs, because most projects seem largely abandoned, except for Thumb-Key, which is exciting, active... and mostly not my bag. 8VIM is a fun version of this, but again, I'm mostly a two-thumber, so these slow me down.
Floris is almost there, except there's little development activity, and the lack of autocorrect keeps me from using it most of the time. The clipboard is great, and the alt-key keyset is fantastic (it includes interrobang!). But the swipe is decent, and it has a 9-pad number entry which - although it can sadly not be made the default - should be mandatory.
AnySoft has some serious stability bugs that keep me from using it.
So I use OpenBoard most of the time, because its autocorrect works pretty well. It has no swiping. It has no 9-key number entry. It has no interrobang. While I like the multiple-choice paste history, most of the time the multi-step paste is just more work.
Gboard has all of these, but it comes from Google.
Keyboard development mist just be unfun; I agree with you: it's a sad state of affairs.