Does 996 yield better results than typical 9-5 work? I can't help but think that at that level of time investment, particularly for knowledge work, you are getting negative marginal benefits on time spent at work.
The 4-day workday movement is testing the opposite hypothesis, and I've heard of a few tech companies testing the waters with e.g. time limited half day fridays (marketed as a post-covid recovery or summer perk). The questions are what they took from the results and whether they'd be willing to be seen to take risks with their biggest cost when the expectation is for a recession.