Proton and Tutanota are the most privacy-focused ones, offering zero-access encryption. The flipside is that they are a bit more expensive and less easy to use with third party email clients.

There are a number of alternatives like mailbox.org, Posteo and Fastmail which are cheaper, and less private than the above two but arguably still better for privacy than Gmail (in that their whole business model isn't built off capturing and monetising your data).

Personally I use mailbox.org and have no complaints. I use it with third party clients like Thunderbird for desktop and FairEmail for Android so can't speak to how good their web UI is.

I also strongly recommend getting your own domain name to use with your email. It means if you ever want to switch providers in future you won't need to change your email address.