I honestly don't think it's hardware - I've had a couple of locks/crashes on my 14" MBP Max, suspect it may be power management or driver related (yeah, Macs still have drivers, they're just built into macOS) as mine is usually if the machine has been idle or wake from sleep.
Hardware test passes and if the machine is heavily loaded it's 100% fine. Normally with hardware problems (e.g., memory/cpu errors) its the other way around - fine when idle and crash on stress test.
Will bet that next macOS point release it is sorted. Mine hasn't crashed in several days now so maybe the recent point update may have fixed mine as per another poster above.