> just to reach pihole at home, that sounds like overkill.

Host AdGuard on a VPS (same one as the VPN?). Then you can use it from everywhere.

I doubt the VPS/VPN route is for the majority of people, but if "you" are one of those, then yes, it would make sense.

For everybody else, $18/year vs $5/month for a VPS should be an easy choice.