Bare with me as I try and explain my issue. Twice now I've run into an issue when sailing between 35-45 into the wind. It's almost like I'm stuck in irons but the boat is moving at about 4-5mph. I cut the wheel all the way to leeward but the boat stays into the wind at around 35-45 degrees. The boat isn't particularly heeled either. Would dumping the main help regain control? It's going to be a real mental adjustment not having the mainsheet in my hands at all times. I love not having sheet lines in the cockpit but it's a naked feeling at first with just the wheel.
It's been years, but I used to use two CP25's in a sailing school environment.
Yes, the sail plan can overpower the helm.
So yes, sail trim is your answer.
Tie the rudder amidships, and practice sailing/steering with the sails ...