I would suggest either protonmail or tutanota. Safe-mail is not safe and most others are not as they do the encryption on the server end and thus also store the keys. If LE asks them they must hand over the keys and thus LE can view any emails you have sent or received. Both protonmail and tutanota encrypt via your browser thus they cannot hand over keys as they do not have them and good luck to LE trying to decrypt anything.

P