Rainbowdragoneyes makes good chiptune music (no fusion). Very underappreciated, it feels like.

Edit: added link

Unless the app allows you to export/import your settings, unfortunately the answer is no.

This is because F-Droid builds its own installers and signs them with their own key. Android (sensibly) does not allow upgrading a package if the signing key is not the same.

Mullvad DNS works well for this too: https://mullvad.net/en/help/dns-over-https-and-dns-over-tls/

Using DoH (DNS over HTTPS) means it should work on networks that try to block usage of private DNS servers.