The problem with your question is that it makes no sense.

The rules of banking is that a bank is never insolvent/bankrupt.
And yes, it is circular reasoning.

The truth is that all banks are overleveraged and if they actually had to mark-to-market or keep any accurate accounting measures, they are way passed bankrupt.

But, as long as the music keeps playing, the game of musical chairs continues. As soon as the music stops, all the little people will find they have nothing.

Even if the bank looks solid, it could, at the very last minute, take on a huge loan, and that loan will be paid first.

This is the biggest advantage cryptos have. It is your money. You are not left in a position of asking the bank, please, may I have my money back?