The plumbing diagram at
https://www.trailmanorowners.com/for...&pictureid=435
was made almost 20 years ago, and has stood the test of time. My 2020 TM has 4 drain valves. While I can't guarantee that nothing has changed for 2022 (I think no one can except the factory - did you ask them?), I'm not sure why there would be a change. Can you open the cupboard and see where the plugged pipe goes? I suppose it is possible that TM developed a new way to drain the fresh water tank, but you should be able to see it.
Bill