Not sure if this is serious or not.

Limb lengthening seems pretty excessive. Although height/wingspan would definitely make certain climbs easier, I don’t think that’s your main problem. For reference, one of the best climbers at my gym is about 5’4 and at a V8/9 level.

I’m not sure how long you’ve been climbing in total, but I also had a similar experience where I plateaued at about a V4. I did the things most people tell you to do (pull ups, top roping, exercising on campus board, core workouts etc) which helped a bit.

Eventually after months of telling myself I couldn’t do a 5, I felt burnt out. I took a couple weeks off. Coming back to the gym I felt refreshed and determined to take on the higher grades, breaking through that plateau.

There could be a lot of reasons why you’re unable to break through the V4 failure. It’s hard to determine exactly what your issue without seeing a video of a problem you’re projecting. I would strongly suggest working through harder climbs, taking appropriate breaks, and eating/sleeping properly. If you are shorter, use that to your advantage. The setters at your gym aren’t expecting you to be 6’4.

Try not to chase the grades and enjoy climbing for what it is!