Is there a good way to block the spam without it even hitting my laptop?
It seems the main problem is that hosted mail servers accept spam in the first place. Wouldn't it make sense to disallow blacklisted IPs right during the connection phase, so that they can't even send data to me?
By the way, twenty spam emails a day is a tiny amount. My email accounts see hundreds a day after no-duh filtering.
I use mailcow self hosted, which allows for fine tuning. I have a list of recipients I trust, and that goes in mailbox, next is a folder for unqalified mail, and finally 100% spam.