In the end it all points to block 57043
It makes sense based on everything I'm seeing, plus external sources seem to confirm it:
Also worth noting Block 170(Satoshi Nakamoto to Hal Finney 10BTC test):
Block 170 is the first payment from one person to another and was a gift, not a purchase.
Also, for the people saying he made a mistake spending 10k BTC for pizza, you can see that it was clearly not his last 10k as that address received more than 80k BTC over time... 😄