. You are looking at this wrong, the available funds on Coinbase are fiat currency, exactly the same as if they were in a regular high street bank. I like many digital nomads get paid in a myriad different currencies and a selection of cryptos. By keeping them all in one location, it is easy to calculate and pay any taxes due. I don't have to buy cryptos with the customer deposited funds, I can draw them as cash from an ATM, use them to pay mortgages and bills etc.
My Coinbase account showed many times over the required funds as available, but I was denied. I don't even use a bank account anymore, I just use my Coinbase Visa Debit Card so it put an end to my application. Many digital nomads must be in this position, so it seems ridiculous. Best of luck.
Pay for the 30-day extension and claim the 1900 baht fee back from your airline. It should be no issue as it is due to them that you need it. Hope you enjoy your unexpected extra time.