Setup a DNS server on a dynamic public ip - Lemmy.World

Hello! I want to set up a pi-hole on my home and connect from my parent’s. Both setups have a dynamic IP assigned by my isp and are different networks. I have a couple of questions: 1) I can get a domain that updates automatically. But how would I resolve it on the client side? 2) Is there any way to authenticate on the server? By Mac maybe? That can be spoofed right? 3) Can setting up a VPN solve both (1) and (2)? 4) Is there any other way? Thanks!