I wonder what was preventing you from doing a chargeback if your flight was cancelled with no reasonable alternative? Then it's between the airline and their bank.

I did exactly that with Aeroflot - I had tickets to Thailand during Covid back in 2020, and obviously the flight was cancelled and Aeroflot was talking about vouchers and how it would keep holding passengers' money to survive through tough times - I've just filed a charge dispute with Russian branch of Raiffeisen and got money back in a month.

And since the USA is the proverbial land of the credit card and chargeback, what stops you?