I’d prefer a such a privacy oriented company to be more open to anonymous payment methods.
Overall, Proton seems like a little more privacy-conscious Gmail alternative.
Tuta
doesn’t use Google/Apple notification servers
encrypts more stuff than Proton
PS In both cases, emails are not end-to-end encrypted. Even though both are marketed with E2E encryption by default. Again, Sun Knudsen has a great video about the topic (youtu.be/G2Jh8bQ2wM8&t=501).
Also, as far as I remember, Proton is more expensive while having less features (the cheapest option) than Tuta.