Are you suggesting OP spread the repayment over several years by only making minimum payments? If yes, wouldn't the much higher interest charged on the credit card evaporate the 4-5% you could make via the HYSA.

If you have the cash, put it in a HYSA then make large enough payments to pay off the debt before the deferred interest is added back to the balance. That way you make a few $ and pay zero $ in interest.

If you can only afford to make minimum payments then the deferred interest card ends up being different that a regular credit card regarding how much the borrowed money cost. I've done these loans a couple of times with Home Depot and a HVAC replacement. The interest is delayed for a period of time but not forgiven unless paid in full before the time is up thus I would divide the balance by the time factor so being extremely disciplined with the payments, the debt would be gone before any interest would be charged. I got to use their money to fund a project.