Your board is too big and too wide and thick to effectively trim so in essence the board goes where it fits. As the wave steepens up the board almost flips. Your next step is to get stronger to catch your own wave and ride a better board to control it along a trim line.
Commented on Progress update, practicing backside ...
07 Mar 20:23
That probably won’t work. The wave is 3d and you approach is flat and one dimensional. Think of it as flying or riding a bicycle and stop trying to balance on the board. The more you turn the more on rail you are and the more hydrodynamic you become. Keep practicing the turns and hold them longer and it will click when you stop fighting the turns