Organic Maps is available on Linux! It’s on flatpak and several package repos (but not apt). I don’t know how long it’s been there — I just discovered it.

The splash screen cautions that this Linux beta doesn’t have parity with the mobile apps yet, but it’s still a huge leap over Gnome Maps. Vector rendering, so you can zoom in as far as you want, and free / open source / not shitty (notwithstanding the big scary EULA, which just contains all the OSS licenses for all the pieces).