You just need to block your body as if you were a hard sandwhich, try it with a 180. Pull your knees up and block yourself. Try to separate your legs a little bit before junping to gain stability.

Square up with the jump and rotate parallel. Your issue might be that you're rotating your shoulders at an awkward angle, sending u on your side or back.

When you initiate the spin, don’t let your head drag behind, make sure you’re leading with your eyes to look to your landing and spot it, so you know where to end your rotation or lean forward to stay balanced and land comfortably.

It really helps for me to just lean back a little, relax, and keep a shoulder width stance. When you wind up, also keep a decently wide stance and put use your arms to wind up for it👍

I had the exact same problem with my 360s and I just tried to spot my landing and stay upright when I reach the ground.