Wanted: E-mail provider with support for external e-mail aliases?

I have forwarding e-mail addresses for my personal website and my party, which forwards business e-mails and other stuff to my main mailbox at @mailbox_org. Until last year, I set up these e-mail addresses as ‘external aliases’ at mailbox.org and was thus able to send e-mails with the identities of the forwarding e-mail address. Until mailbox.org decided to move this feature from the 1€ plan to a 150% more expensive plan.
Now I’m looking for an email provider where I can verify my email addresses and send messages from them. I don’t need any space for the mailbox, just SMTP.

If possible no GAFAM, with Yahoo the feature is theoretically available, but broken. Preferably nothing from the USA, even better of course would be outside the FVEY zone. If it’s free that would be awesome, if it’s <=12$/yr, I’m fine with it.
#askfedi #email @asklemmy