Lol, I remember watching a video on how to rolling hop where the guy didn’t even bother to show himself doing one. All the videos I could find were just plain terrible.
I don’t know how common it is, but I did have issues with wrist pain when I first learned to hop. It went away later, I’m not sure if my wrist got stronger or I just learned how to hold the handle properly. I’m guessing it was the latter. Try and pull up as little as possible on the handle when you hop to put less strain on your wrist. Remember that the bounce from you legs is where the hop comes from, not the pull from your wrist. All your wrist has to do is hold the unicycle in place when you go up. This is easy to visualize, just imagine the unicycle is a pogo stick with your legs for springs.
Don’t cut your frame the seat height looks just fine. I had a response written up and then I realized that I hadn’t watched your video. It looks like you’ve almost got it down to me unless you are trying to get like two feet high or something. I think you will probably do better if you try to actually hop up curbs instead of just getting air time. That way you can develop better control as you will have something to gauge your height and length by. If you want, you can set your cranks to be in the right position when you get to the curb by setting your unicycle in the position you want it to be next to the curb and just rolling backward. It also can be easier to hop up a curb then just get some air because you don’t have to go back down as far before landing.
Another thing that might help is a different pair of shoes or pedals. It looks to me like your feet could be sliding off the pedals too easily. Some pedal/shoe combos just don’t work well together. A different pair of shoes or pedals that grips better could help a lot.
One last thing, it’s great to practice side hopping up stairways to develop your technique and control when hopping.
I hope your wrist gets better soon, a doctors visit shouldn’t hurt. Good luck!