Is it at all possible that SBF is "merely" inept (yet still culpable)? Or is there any way to know whether SBF knew what he was doing was making FTX insolvent?
No. His resume shows he's smart enough to understand how market-making and trading works, he just bought into his own mythos and thought he could out-trade the world.
If he was actually as skilled as he thought, his strategy could have made him unimaginably wealthy, but he wasn't.
I'd compare it to a magician throwing swords at an assistant on stage. You better be sure that you know what you're doing before you do it.
no he was bragging - a lot of the "trading" alameda did was participating and orchestrating "boxes" like what he so smugly described in the interview, which was horrifying to listen to.
The problem with claiming he was just inept is that he was actively doing things to hide the insolvency - pumping the value of assets in which he controlled the market, doing deals with other insolvent entities to hide any defaults, and conditioning deals on collateral being held on FTX. It was very clear many months back that Alameda was underwater, and that whoever was their lender was going to face a massive default. SBF was both the issuer, borrower and lender of the FTT tokens - and none of that money was meant to be associated with customer assets. There are some simple questions of "Why did SBF do a load of deals in the spring which were clearly money losing?" and the answer is "The only possible reason to do those deals is to hide the massive losses he'd incurred".