Since you’re picking a new provider anyway, it’s worth thinking about how you pay. A card ties the account to your name even if the mail itself is encrypted. Tuta and addy.io both accept Monero, and Mailbox.org lets you pay by bank transfer without a card. For aliases, addy.io with any of those works really well.

For the alias part, addy.io is great, and it accepts Monero, so the alias account isn’t linked to your bank either. Tuta takes it too. I keep a list of email providers that accept XMR if you want to compare more: https://xmrlist.com/businesses/email-providers