Ignoring everything there is on sleeping, what your body needs, how it can operate et al.
My only thoughts on this – we are all wired differently and can all handle less or more sleep.
Do you need to work every day to 2 AM to be successful?
My only answer is whether the work you are doing at 2 AM is still as useful as the work you were doing at 9 pm?
If so, then yes keep working till 2 AM and become successful.
If not, then yes stop working till 2 AM and become successful.
It’s not the time you are putting into the work that matters, but rather the work that you are putting into the time – if the quality isn’t where it needs to be than that should be your biggest concern and not what hours you are working till.