Another vote here for Fastmail. I also like Posteo, Mailbox and mxroute, but these are not as fully featured - which may be perfect for you if you're after email only. What I really like about Fastmail is that on top of being a customer-focused business (rather than a customer is the product business), they offer a really snappy web interface with excellent search - and they are extremely compliant with email standards, building everything on JMAP.
I do not like Proton or Tutanota. I have used both, including using Proton as my main email account for the past two years. I do believe they are probably the best when it comes to encryption and privacy standards, but for me it's at far too much cost. Encrypted email is almost pointless - the moment you email someone who isn't using a Proton (or PGP encryption), then the encryption is lost. Or even if they just forward an email to someone outside your chain. I would argue that if you need to send a message to someone with enough sensitivity to require this level of encryption, email is the wrong choice of protocol.
For all that Proton offer, it results in broken email standard compliance, awful search capability and reliance on bridge software or being limited to their WebUI and apps. And it's a shame, because I really like the company and their mission.