Fiat is a terrible investment, as advertised. Central banks make it clear they are target inflation and that you should expect the asset to depreciate. I don't think anyone expects to get rich keeping their money under their mattress.

May I ask if this bank was insured? What country was this in? I'm surprised, because this is something "tradfi" is usually very good at. At any rate, that really sucks and I wish you a full and speedy recovery of your money.