It is possible if you use pivpn (or any other VPN software) and double hop it to your pivpn provider.

Device -> pivpn (uses pihole) -> mullvad -> internet

I just get the wireguard configs from mullvad and edit them to properly work. Also works to get around device limits of the VPN.

I use Quad9 for my upstream.

I would stay on both. Keep reddit just for the more specific subreddits I like that aren’t big here.