Good that it’s working (kinda).

So it sounds like your DNS resolver is botched. Id dig into the doc on how systemd-resolverd should look and see if you can’t rectify what went wrong (the arch wiki should have examples of what a default config looks like).

I don’t remember if arch uses cloud init configs but it being reset at boot feels like a cloud init config problem.

Let us know the following

If ping works for: localhost, your gateway, 1.1.1.1, google.com.

The contents of your /etc/resolve.conf

If you have a tun0 interface (ifconfig or ip a)

You said you uninstalled tailscale. Are there any running process or active systemd units laying around?