I’ll give Magic Earth a go, but osmand is just missing a bunch of stuff I got used to having I guess. The actual map part is fine.

I use DAVx⁵ myself. It’s not ideal aesthetically, but honestly not a thing I worry about.

I’ve been hoping for one for some time, but it wouldn’t be a smooth sailing even if everything was perfect. Get a pixel, install grapheneos and see if you can cope with it. I’ve been running it for a year now - lack of decent map app is my biggest issue that’s left. Waze is great for driving, but useless for everything else; it’s also owned by google. Most other apps are just reskinned google maps and don’t even load without gapps.

And I’m a sysadmin. My degoogling journey began in 2018-2019 with running my own nextcloud for files, photo backup, contact and calendar sync, as well as my own email server. All that to say that I’ve had it fairly easy to ditch play store on a phone, but that’s not what most will experience.