The vast majority of the Android/iOS flamewar is pro Android on fedi (mostly Mastodon for me). I usually don’t bother but I thought my comment was at least sort of funny? oh well.
I can reply from ANY address from my domain including the exact one that was used to send me an email.
I can “deactivate addresses” by sending messages to a particular address straight to trash with rules.
Edit: turns out Fastmail has a masked addresses feature built in, separate from a catch-all. It’s basically simplelogin built in, if you want to enable it. Proton is looking more and more overpriced.