Oh, wow! I hope no one accepts an online CPR cert. I teach CPR/AED/First aid and the number of people that need help in doing it correctly is small, but worth every moment spent in class for the person that might need their help one day.
If you already have taken the course several times, you should do the “challenge” or an abbreviated course for recertification. But getting your hands back on a manikin every couple of months (let alone two years) is a good idea. It could save the life of a family member or friend.