One possible way to do this: rather than simply burning hashes for nothing, Anubis can burn hashes to mine crypto. This way, the bots pay for the infrastructure they consume, at least in part.
Combine with heuristics like in the article, so you can crank up the difficulty only for likely bot traffic, and you've got a bot supported site.
CPU crypto mining stopped being viable over a decade ago. If you want a client to pay for the infra cost of their request, they're probably going to need to work for hours to do so.
Disappointed at the lack of replies here, I've had a similar thought before and I'd be curious to hear about the technical viability of this
This was done in the past[1] and was widely regarded as a "cryptojacking" scheme serving "malicious" content to users.
[1] https://krebsonsecurity.com/2018/03/who-and-what-is-coinhive...