KE wide open? Depends on the plane/engine... mainly the plane if the engine is sized reasonably. My 2M pattern ship will hold KE easily with almost no rudder input at 1/3 throttle. I had a 25% Decathlon that would hold KE at a jogging speed at about 50% throttle. I've had other planes that can't hold KE without descending wide open. The key to lower throttle KE is not rudder as many believe, it is forward side area. You will notice many pattern/aerobatic ships have canopies shifted forward... that's why.

Villa has the CG effect of KE pitch issues correct. Wing incidence can also cause issue as well as some other things I won't bother with in the beginners forum. Moving CG is generally a good fix if other tests confirm your CG is out of whack. If moving CG is not an option, or not desired for other reasons, read up on how your radio mixes work and mix rudder(master) -> elevator(slave) to mix out the undesired pitching. I'd suggest getting a helper and putting the mix on a switch. Leave the mix off for takeoff incase the mix really jacks with you. Flip the switch and test KE both directions (left and right rudder), have your helper write down what happened. Land, adjust mix, rinse and repeat until it tracks nice and straight. FYI, many plane will have roll coupling too with KE, i.e. they will try to roll upright or on thier back. Dihedral and other issues cause this...easiest fix is again a mix rather than chopping the wing to reset dihedral, etc.