Kind-of an aside, but you’d probably be better served setting up a dedicated VPN qube rather than a multi-purpose qube in which you also run the Mullvad app (I think this is what you’re saying you’re doing, but I’m not certain). This ensures your traffic doesn’t accidentally go clear if e.g. the Mullvad app crashes.
The instructions here are up to date and not too tricky to follow:
This is also IMO more in line with “the Qubes way” and will guide you toward patterns of use that are more amenable to finding good help here, I think.