In theory you could open up your protonmail account over tor and with bitcoin (or does that not work anymore?).

Its been a good while since I tried them out. Why I don't recommend them anymore is because when I didn't extend my subscription in time (expecting an account downgrade), my mail was locked and emails hold on to as random. Allowed to login only for payment.

That was one red flag from me, the second was when they shared IP address logs of a French protestor. E̶v̶e̶n̶ ̶t̶h̶o̶u̶g̶h̶ ̶a̶t̶ ̶t̶h̶e̶ ̶t̶i̶m̶e̶ ̶t̶h̶e̶y̶ ̶h̶a̶d̶ ̶a̶ ̶n̶o̶ ̶l̶o̶g̶s̶ ̶p̶o̶l̶i̶c̶y̶,̶ ̶i̶f̶ ̶I̶ ̶r̶e̶m̶e̶b̶e̶r̶ ̶c̶o̶r̶r̶e̶c̶t̶l̶y̶.̶ ̶O̶r̶ ̶i̶f̶ ̶I̶ ̶d̶o̶n̶'̶t̶.̶