I can’t change my router’s DNS

Do you mean you can’t change the DNS server in the DHCP settings or the server the router itself uses? In the first case you might be able to use Pi-Hole’s DHCP server instead, while for the latter it shouldn’t be an issue - I actually usually leave upstream servers configured there to avoid loops. BTW, you might also be able to flash OpenWRT to your router

A computer that is used by a user, aka “not a server”

Not true, SSH keys need their passphrase to be used. If you don’t set one, that’s on you.

Probably not worth trying to actually use today. I’d leave it as it is, imo it’s better as a small piece of history - Android on PC is pretty niche