There are 3rd party providers who will sell you tokens you can redeem for Mullvad over lightning. Very easy to do, anonymous, and convenient.

Mullvad itself accepts Bitcoin, but only on-chain currently (although I’m sure that will change soon).

I’ve used both IVPN an Mullvad, but currently I am using Mullvad because of their incredible track record of keeping zero user data, their optionality, and their new ram based server model. Both are great no-KYC VPNs though.