This. For this reason I regret making an @icloud.com cause now it’s permanently attached to my Apple ID. Also, it only offers 3 alias, what is up with THAT!?I'll consider switching back once iCloud adds status syncing across devices. It's annoying to read email on my iPad/MacBook and still have my iPhone show that I have unread messages until I refresh it. Same for flags.
FastMail has had this for years and has always been rock solid. (Pretty sure Google/Microsoft paid plans offer it too)