An FDroid desktop client that adb installs APKs would actually be lovely. I pretty much exclusively use FDroid, but I gotta say I unfortunately find all their frontends to be rather buggy and with very little user feedback when things break (repo updates are hard to observe, downloads hang, updates mysteriously fail)

I feel you about the frontends being buggy. Right now I've settled with Droid-ify[1] for doing my F-Droid browsing.

[1] https://droidify.app/