I had (still have but they don't send as much lately) a similar problem but with email and Outlook.

I get like 10 spam emails in my Junk folder every day from the same domain but with different subdomains, which would be fine if I could define a rule to delete all emails with the matching root domain BUT rules don't work on the Junk folder (facepalm).

I can't fathom why are they not blocking the root domain outright, I'm pretty sure it's just for spam. It got so bad that, at some point I wrote a script that deletes these emails periodically - but getting that was not easy since I needed to use OAuth to get an token.