If you make Tailscale your VPN in Android it will never be killed. Mileage may vary depending on flavor of Android. I’ve used this on stock Pixel and GrapheneOS.

Under Settings > Network and internet > VPN

Tap the Cog icon next to Tailscale and select Always-on VPN.

There’s an app to pull the Astronomy Picture of the Day and set it as a wallpaper

https://play.google.com/store/apps/details?id=uk.co.jakelee.apodwallpaper

On the topic of build times, it took me too long to learn that nixos-rebuild supports remote build workers and targets.

For example, if I am editing on my laptop, want to build on my desktop, and apply the build to my file server, then I’d run…

me@laptop$ nixos-rebuild test \
--flake ~/wherever-it-lives \
--build-host desktop \
--target-host file-server \
--use-remote-sudo

The host names should match the name of the nixosConfiguration output from your flake. If they don’t I think you can specify like, --target-host .#some-machine

Remote sudo avoids having to SSH as root.

Bonus tip: Having Tailscale on every machine makes this work reliably from anywhere, network speed as the limit.