ultimately, it’s the choice to use a credit card that created the issue. As Proton’s statement mentions, it also accepts payment by cryptocurrency and cash, which could be better ways to keep your information private if you absolutely need to.

The FBI had the payment data and served Proton with a subpoena, they had no choice but to tell which account it was for. The data is still encrypted, though.

LMDE is Debian based whereas the regular Mint is Ubuntu-based, which probably explains issues you’ve experienced.