I genuinely enjoy GBoard. Now; I get it. It's not for everyone and it hasn't got the best...track record.
It does actually surprisingly work very well; and I have yet to see anyone on the FLOSS/F-Droid side of things manage to create a keyboard with similar functionalities. I get that it may be an impossible ask, but it seems like nobody on F-Droid is interested in creating a keyboard inspired by GBoard that actually has all the similar QoL features that GBoard offers.
I have a Galaxy Fold 4 so I have both Swiftkey and Swiftkey Beta installed and use a Tasker profile to set the default keyboard to one or the other depending if I'm using the inner or outer screen. I did this so I could have a split keyboard when I'm using the inner screen (because I'm holding the phone with 2 hands and it's easier to type this way) and the regular keyboard when I'm using the outer screen. It was a little finicky to set up but truthfully I have become so used to it that I honestly forgot that I had 2 different keyboards until I started thinking about it because of this post.
I also have a fold 4 and I do this with launchers. Using Niagra on the outer screen since it's mainly vertical and I use SmartLauncher on the inside. I'm using Bixby routines to do it though. Never thought about doing it with keyboards though. TBH I rarely use the keyboard while folded anyway.
I'm still using Minuum Keyboard. I think that QWERTY on a touchscreen keyboard is counter intuitive, slow and cumbersome. I wish more keyboards adopted single line keyboard layouts with fuzzy typing.