I've recently been setting up web servers like Forgejo and Mattermost to service my own and friends' needs. I ended up setting up Crowdsec to parse and analyse access logs from Traefik to block bad actors that way. So when someone produces a bunch of 4XX codes in a short timeframe I assume that IP is malicious and can be banned for a couple of hours. Seems to deter a lot of random scraping. Doesn't stop well behaved crawlers though which should only produce 200-codes.

I'm actually not sure how I would go about stopping AI crawlers that are reasonably well behaved considering they apparently don't identify themselves correctly and will ignore robots.txt.