Proton

proton does not advertise themselves as anonymous email.

So, i just checked, and they actually do (albeit with caveats, including not using your name when signing up, but no mention of when paying) here and here among other places.

I see also that those pages are promulgating exactly the "anonymity vs. privacy" false dichotomy that you are. Proton writes (emphasis mine):

Privacy means controlling who receives specific information. In the email context, this means encrypting your message so no one besides its intended recipient and you can read it — not even the service provider.

Their very narrowly-scoped definition of the word privacy is inconsistent with how most of the world uses the word. Proton is defining email privacy to mean solely the confidentiality of the body of the message (which they also provide a trivial-for-them-to-circumvent protection of, incidentally) but the word "privacy" elsewhere (eg, in law, technology, academia, and colloquially) has a much broader meaning.

Or, to put it more simply: Category:Anonymity is (literally) a subcategory of Category:Privacy.

Proton isn't even consistent in their own usage of their absurdly-narrow definition of privacy: in their How to send an anonymous email guide they write:

Where your email provider is based affects your privacy. Privacy laws can vary dramatically, and some countries have data retention laws that require companies to store and hand over sensitive user data. Email services based in a privacy-friendly countries, like Switzerland, can offer stronger protections.

Do you think by "privacy" and "sensitive user data" they're only talking about the body of email messages here, as per their earlier definition?

And, regardless of whether or not a company advertises its services for anonymity (as Proton does, it turns out): after clicking the above links and thinking about it a little more, do you still think that retaining and revealing links between users' pseudonyms and legal identities is really not a privacy issue?