I've done this before. It becomes tedious to maintain, but I can imagine myself doing it again in the future to allow me to do what cannot be done in the common clouds (iCloud, G Suite, O365).
I would love a whitelist-only inbox. I'm sick of spam, marketing mail, etc. I'd like one public email address that catches all the garbage. Then, I'd like a private email address that accepts emails from my contacts, and bounces the rest.
This is really easy to set up using Dovecot Sieve [1]. I set it up the other day to bounce reject messages that had too many swear words as a proof-of-concept for an idea a Facebook friend had about making sure people stay nice in email. The syntax of the server-side filters is a bit strange but there's even a Thunderbird plugin that allows you to edit them from the client.
I would love a whitelist-only inbox. I'm sick of spam, marketing mail, etc. I'd like one public email address that catches all the garbage. Then, I'd like a private email address that accepts emails from my contacts, and bounces the rest.