Thank you for the answers!

Because that's not how aircraft work. In real life, the yaw controls are used sparingly and in conjunction with the roll controls. To understand the why's and how's of this, you're going to have to read a bit about aerodynamics. I recommend wikipedia.

this plane i made is the best one ive found so far for yaw, the problem is the normal rudders either stall due to too much movement or are too high up and thus roll the plane as well.

You can. Just hold the yaw button long enough while stabilizing using elevator and ailerons and you should turn. In fact, that's how yaws work in real life.