I don't know if the picture will show so I will describe. I don't know if my 2019 Wildwood has a bypass valve on the hot water heater. There are two valves. One on the cold line and one on...
I don't have this system but I suspect the valves are quarter turn plastic on plastic which tends to take a set over time which makes them difficult to turn. You may want to hold the valve body while turning the handle.