It was becoming obvious that to buy Twitter, TSLA value would have to decline severely. IIRC, Musk only got around to selling $8 Billion pretax before quitting.
Musk thought he could afford Twitter. He sells some TSLA and the market collapses, and he suddenly decides against it.
Everything else is smoke and mirrors. Musk doesn't have the cash for the deal anymore (maybe he never had the cash for the deal). I guess Musk is looking at the $1 Billion ejection clause now and trying to weasel around it.
But at this rate, it looks like Musk owes Twitter $1 billion cash for this broke deal.