I love fastmail, I switched from Proton a couple years ago after deciding the trade offs to have encrypted email were not worth it, since even if I fully trust Proton, most emails come from or go to AWS, Outlook, or Gmail anyway. I have been extremely happy with the service. Fairly priced, very fast even with a huge inbox, and they don’t add unnecessary features or bloat. I thought I would use my OS’s mail apps but the fastmail app and website are so good I just use that.