Proton hijacks your screen with full page ads. They are very pushy with it. I recommend you find something else.

I clicked an email notification and got this instead of the message. It's gross.

I see Proton and Tuta recommended here, often.

I also see complaints about both (Proton's politics and Tuta's tendency to lock and clean free accounts).

Both seem better than Google, who seem to be tightening their grip on those unable to walk away.

Proton is definitely no good. Ads, freemium, AI garbage, Bad 3rd party client compatibility, CEO loves Trump, etc.

Its better not to put all your eggs in one basket so dont try to find a single provider for all your needs.

All email services will be able to read your emails unless you encrypt them yourself (PGP). So there are no "private" email providers really. What you should look for is just a functional provider that works well with proper clients like Thunderbird (available for desktop and mobile).

This is a list of many tried and tested servers, just pick any of the "OK" ones: https://providers.delta.chat/
Deltachat is an app that allows you easily use email in and end to end encrypted way while making it look like a standard instant messenger. For this to work properly, the provider needs to support 3rd party clients properly, so this list gives you a good look at the technical quality of the email provider.

See how Outlook, Proton and Tutanota are non functional? Thats because they dont implement the email standard properly in order to lock users into their platform and apps.

I'm on https://mxroute.com/ they are cheap and hands off. Sometimes that means you get yelled at in the beginning to RTFM because they don't have the time to deal with each individual, just follow the manual and you never need their support.