Here's my take:

* JA3s are mostly useless. JA4s supersede them entirely.

* Using JA4s in rate limits is pretty useful and helps a lot against proxy scraping. It was not very helpful in this attack.

* Bot detections are somewhat helpful but they don't solve scrapers/attacks by themselves. They're useful as a 2nd/3rd data point (eg. low bot score + bot detection + something else)