Your elevator halves not aligned. Left elevator is lower than right elevator. It will cause roll to right. Thus, left aileron trim.

Fix the elevator alignment first.

Two ways to align.

First method.
Going Dual Elevator servos. if you can't find the stock elevator control horn, cut it off. Cut out the elevaotrs (CA hinges?). harden the right elevator on the control horn location (may want to peel off a little of covering to add epoxy). It has slot already cut out.
Make both elevator halves even thickness on control horn location. Drill and use Dubro 493 or something similar. Don't use reversing Y. USE separate channel to use programmable mix or any other dual elevator function on the radio.
Use robart type hinges or regular plastic hinges if you have hinge slot machine. CA hinge is really hard to remove. I used Robart hinges.

The other way.
If you can, cut the center of the elevator joiner, add two 1mm thick x 5 or 6mm width carbon strips on top and bottom with epoxy while elevator halves aligned. Since the stock joiner will stay in angle, you may want to shim between the thicker strips on top and bottom.