I personally use mullvad for all outgoing traffic and then airvpn for any let forwarding I require. Basically airvpn is exclusive to incoming traffic, like my self hosted services or game servers, and then anything I do on the internet routes through mullvad. All setup through opnsense since they both support wireguard.
I always had issues with proton’s port forwarding being reliable in the past. That being said, if you need things like video streaming services, mullvad seems to be having a hard time with these recently where as proton worked well for me back when I used it (unsure if that’s still true).
For me, it’s just that I don’t want to have to turn the console on with plans to play for 1 hour only to be introduced to mandatory forced updates or show installation times that eat that entire hour away anyway. I just want to play my damn games, not to mention 100% offline if I so choose to.