At all companies I've been at or have intimately known about, there have been clear guidelines for promotions and examples to look at. These are medium to large companies. FAANG and non-FAANG.
I'm sure you're right in a lot of cases, but I feel like at most software companies I'm not too far off.
That'd be a very rare circumstance.
In most jobs working 15-20 hours overtime each week only gets you 15-20 hours less for living your own life, nothing else.