I can replicate that in my free account, not in my enterprise. I have not yet tested the others. Suspect it’s something to do with this line in the doc you mentioned, The available characteristics depend on your Cloudflare plan and product subscriptions…digging
The counting characteristics by plan is documented here: Rate limiting rules | Cloudflare Web Application Firewall (WAF) docs
Only Enterprise with specific addons gets extra options for Counting characteristics.
That also doesn’t prevent you from using Rate limit, you’re just locked to it being counted by IP.