Corporate law can get very complicated, but I think I understand the 101 level answer.

If you bought a bank (not bankrupt), you would assume assets and liabilities.

During bankruptcy, the court sells off all the assets and uses the funds to pay the liabilities in order of precedence. When you buy assets from the court, that's it, you don't buy the whole bank just certain assets. Ideally the court would have an auction for the assets, in practice it might only solicit a few offers and take the highest one.

If you bought a few assets from a bank and then the bank went bankrupt, you might face a civil suit. The plaintiffs could argue you underpaid and owe them money. If you convince the court you paid a fair price, you should win.