Sounds like you may be coming in from the 3 channel world.

Rudders are barely used on 4 channel trainers.

Any plane with dihedral will roll and nose down when rudder is applied.

This can be helpful for co-ordinated turns.

But you don't fly the plane with the rudder.
You fly it with the elevator and ailerons.

The PT40 is fairly docile in the sim much like the real thing. I may have turned down the throws a bit to simulate the Alpha.

With the throws turned down and wing lift increased it's a spot on duplicate of the Alpha.

When you move into 3D and aerobatic flight, eliminating all dihedral is a good thing.