I think it would still be a pseudonym since you have credentials to log in to the VPN that remain stable, no?

Anonymous would be like: minute-by-minute you drip Monero into the VPN in exchange for service. It could track you by your IP, but nothing else, and you can change your IP.

You can throw your account and create a new one instead of renewing your "subscription". There's no price penalty for doing that.

Mullvad also accepts cash mailed to them with just an account number to put the cash towards.

If you don't mind loosing your 10% discount, sure