My understanding is that the FDIC does have to orderly liquidate all of SVB's assets unless they find a buyer. That does mean they have to sell all their outstanding treasury and mortgage assets, they don't have the ability to hold them to maturity (HTM).

SVB had billions of dollars in first-lost equity capital that was completely wiped out against those marks, hence them being insolvent. But that means there isn't a 1-to-1 lose for depositors against those underwater assets.