In the spirit of open source thought about it and created sibuna (https://github.com/insanai/sibuna)

It works similar to cloudflare WAF but is an open source software. It can be on your own infrastructures even if its a $5 VPS.

The idea is same let the bot or AI agent do more work than it takes to serve that request. Also it needs to follow rules, similar to cloudflare enterprise web application firewalls. It was OWASP CRS and J4A TLS support.