Testing their patience
I started experimenting with not only serving poison to bots, but to also to waste as much of their time as reasonably possible.
Rate and bandwidth limiting has limits.
A very nice tar pit that drip feeds data is Nepenthes for example (https://zadzmo.org/code/nepenthes/) or re-written in Python if you prefer (https://github.com/NEPENTHESWEB/nepenthes-py).
I coded a tar pit in PHP earlier and now started another that aims to drip feed for maximum waste of time. I'm going to share how to achieve this in the comments.