Okay so it's basically a bail bond, sign over the $2M house to get the bondsman to post $250M bond.
What bondsman has $250M? Even if they did, why would they ever agree to this?
Isn't getting $2M from a defendant on a bail bond less than even the interest you could probably get by just putting your $250M in, say, a Treasury bond over the same timeframe?
For that matter, who's willing to bet $250M at 99-to-1 payout odds that a smart guy like SBF won't be able to disappear and pop up in Dubai or somewhere with no extradition to the US? (Remember SBF probably had the means, motive, opportunity and moral character to siphon a couple hundred million worth of BTC into a wallet there are no records of. And he knew for a long time FTX was going to collapse and he was probably being investigated.)