I used to advocate for fastmail but honestly, it's been awful for me. I had to go back to gmail. Fastmail isn't able to consistently deliver and receive emails, and it cost me a very good job once. More than half of the "verify email address" or "one time PIN" emails don't make it to my inbox anymore and I have to use my gmail address instead. Some platforms just flat out can't send me any emails at all. Multiple occasions of people just flat out not receiving my email, not even in a spam folder. I had a brief period where if I had an important email I'd send it from both fastmail and my gmail to make sure it was delivered. I just gave up and went back to gmail. The state of email is really frustrating and it's not fastmail's fault I don't think, it' more likely google's fault.