

I mean, as far as I know, DNS is decentralized. Anyone can host their own DNS server, or change which server their network/device uses. Google’s is just very commonly used because 8.8.8.8 is easy to remember, but there are thousands of others run by entities big and small, and there’s nothing stopping you from running your own (assuming you manage to get a hold of a static IPv4)
If you’re only going to use it from within your own LAN, then no, you don’t need a static public address