The only surprise will be if the criminal is not linked to SBF
To me the much more likely scenario is that somebody had a persistent backdoor into FTX because it was a shitshow with no security, but they didn't act right away because they were waiting for the prize to get even bigger. But then when it all started imploding, they realized it was now-or-never and made their move.
Smart criminals do stupid stuff all the time.
It would not surprise me at all if this is SBF or another insider’s insurance plan in action.
You don't have to know him; he's made it clear that he thinks rules are for fools.