Hyatt had historically run regular gift card discount promotions, even before COVID. I imagine these stopped because:

1. Breakage was too low. People were actually using the gift cards.
2. Fraud was too high, so Hyatt was wasting money reimbursing customers..

In any event, I assume that the OP has some kind of credit card need to bring forward Hyatt spend by buying cards on-property. Otherwise... https://www.buyatab.com/custom/hyatt/