I used to use Proton with one of the contract jobs I was doing for a while. It seemed fairly adept at doing everything I needed it to do. I think the company I was working with did some work for Proton at one point and that's why everyone was able to have an address. I have been looking into setting something up myself. I did notice a few years ago that Proton did disclose some of their users info in some kind of investigation that was going on. They didn't turn over the emails since those are encrypted, but they did give enough bits of into that the authorities were eventually able to prosecute someone.

https://www.thedailybeast.com/secure-email-provider-protonmail-handed-over-user-data-to-europol/

Not nearly as concerning as what most of the other big companies do with our data, but still important to know.