The always-on on-screen keyboard is bugging me too.
It's a recent change, since Gboard added support for external physical keyboard, but somehow it always detects the slide-out keyboard as being present, even if it's slid-in.
You can turn it off completely, but then the on-screen keyboard never shows up.
In the end I managed to fix it by installing a different keyboard app and disabling Gboard.
If anyone has a fix, I'm interested too