I'm pretty excited about this. It seems like an interesting use case for an e-ink device. Thanks for releasing another program (more useful ports!). Greatly appreciated & awesome work again. I'll see if I can test things for you. I'll let you know if anything arises. Unfortunately, due to my limited skill level I'm not confident in trying to follow the BT Keyboard instructions (at least in its current state, it looks like it's for developers), but maybe I can still enjoy using it.
One suggestion currently, if you're open to them: I'm loving the Shortcuts seen here
https://kindlemodshelf.me/shortcuts.html (not sure who runs it but a Kindle Jailbreaking community was sharing it and it's great, I didn't even know about some of the recent projects until now! It needs more recognition). I think it can quickly open up stuff that is normally launched within KUAL. Not sure if you can create a Shortcut "booklet" or whatever the term would be in this case, for this app. As a user, I love putting all these shortcuts all in one Collection in my library, it's useful..
Edit: I know this thread lists the PW4 model as the tag, but I'm not sure how much that applies to software that's usable on multiple models. It would be helpful for you to clarify a compatibility list you think this would have! On my KOA3 model, I cannot access any of the interface which is shown in your included pics on the first post.. so I'll have to reboot my entire device just to leave the app! I guess one size does not fit all, there's gonna be some variations on the screen size and other issues. So that's troubling! Currently that means it's entirely unusable for me...