I checked out FastMail but it's too bad that while they promote privacy, they require a mobile number to sign up. I understand it's probably used to prevent abuse, but if I'm truly in it for privacy I would imagine this is a non-starter
Privacy and anonymity are different things. It's also primarily a paid service and doesn't take cryptocurrency - credit cards are more traceable than phone numbers.
Ah I see. The distinction wasn't clear until you brought it up. In that case, it makes sense