@jomo #Posteo supports 2 aliases for free, I think, otherwise 20 cents or so per alias. (Depends on how much aliases you want to use.) Mailbox.org also supports them AFAIK.
That + thing you mention is [one](https://jameshfisher.com/2018/04/07/the-dots-do-matter-how-to-scam-a-gmail-user.html) of the "great" features of GMail (actually taht one may indeed not be bad), but not supported by other mail providers. There you usually have to create aliases manually.