Alternative self-host solution that does not require a pi.

Get hold of a functioning spare pc with any os that can run docker containers ( highly recommended proxmox for server and opensense for diy router but that may be to advanced) but most os incl windows should work.

Install adguard home in a docker container. Its a dns based blocker like pihole above. Just set your devices to its ip for dns.

Want it on the go? If you have an internal vpn (wireguard) you can set it up so your tunneling al your traffic from home with all protections persisting.

I have not found a way on ios to block those last pesky ads that adguard misses but its still day and night difference.

You usually only need to specify the internal host ip to setup a port forward. It should forward that to whatever the public ip is at the time.

If the isp is providing the model/router and generally being oppressive i highly recommend researching if you can place your own router behind it.

I believe duckdns has a tool that checks your public ip on a schedule to update your subdomain. (Which they provide for free last I checked)