I've recommended it elsewhere in similar threads, but a nice middle ground between self-hosted email (lots of work), and a straight-up Gmail/Yahoo/Fastmail/Hotmail/Etc account is to buy your own domain and set up your MX records in accordance with Fastmail's (or whoever's) instructions.

I've ported my email address / domain across several hosting providers now. I don't have to retrain anyone.

Obviously this doesn't help you now, but maybe you can start training people on to your new brundolf@superfancydomain.org email address to avoid this problem in the hypothetical future when Fastmail becomes dystopian and gross.