there are several things to consider. You have played with the thrust direction so that is one. That helps keep the unit upright such that all wheels are touching the pool surface.
Have you confirmed that you have the proper length of hose for your pool size? It may sound counterintuitive but having the proper length helps remove hose twisting and keeps the cleaner upright for your depth. You should have at least 1 swivel on your hose. I have 2 and it works fine. That helps the hose from twisting and knotting. Also, ensure you have proper spacing of your floats on the hose.
Is your tail properly sweeping? That helps move debris around so the cleaner can capture it all even if the cleaner can‘t get to a specific corner when it turns the tail brushes through that hard to reach corner.
In the more technical aspects, have you ensured your wheels are turning at the right speed as that creates the force to pull your hose through the water.
While it is a very simple design, there are many things that can affect its performance so you need to review each on its own.
Hope this helps.