Postfix can easily be configured to reject incoming emails from senders without a reverse DNS mapping for their IP address, which makes it reject a lot of spam.

For spammers with reverse mapping greylisting still works fine, they almost never retry.

Certain commercial spammers (hello China :-0) use software which can be filtered with a just one rule matching their sending software, which is "nice" enough to display its name in their mail headers.

And last but not least spamassassin / rspamd work fine to filter whatever comes through.

In the end I get less than 10 spam emails per week. And these go into a separate mailbox filtered by good old procmail, based on spamassassin's ratings. I check the spam inbox maybe once a week for false positives and more often than not the box is empty.