I also have the back propped up like you mentioned with the built in lifts
Ah hah!
Yeah, there are some ergo keyboards that have that "reverse tilt" built in. They're aimed more at being easier on the wrist than at trying to permit for long nails, but they do exist.
e.g.:
I also have carpel tunnel
That'd be an argument for a keyboard, like, a mechanical one where you don't bottom out the keys on press, and then training yourself to not bottom them out, which is a big argument mechanical keyboard fans have for theirs versus rubber dome keyboards. And you need a fair bit of key travel for that, yeah. Hmm.