We should just start from simple basics..

Before flying, set up your plane on your bench or ground.
Raise the tail until you get a 0 degree reading on a robart incidence meter or similar when measuring the wings LE to TE center. Then take a horizontal stab measurement.

I think you have an Extra, which should have a 0 reading from wings to stabs. Both must read 0 each side. wing/stab root and outer tips, check 10x
Turn radio on and and carefully examine your control surfaces from last flight. I asume you had it trimmed to fly as neutral as best possible.
Write down any trim that is not centered and record radio trims also.

The engine should also be at 0 degrees to wing and stabs, this is harder to measure and you maybe able to get away with leaving it for now.
If your wings and stabs are not 0 to each other, then this must be modified, you cannot counter trim this and expect good flights.

If they are all at 0, then check the controls and try to center everything manually via linkage adjustments, after the servos have been centered per radio.
All subtrim and EPA should be at 0, not -30 or plus 20....
Get the linkages and servo horns as close as possible to neutral, then adjust subtrim and EPA. Values below 10 are ideal.

Add 20-30% expo all around except throttle for a start. Depending on radio brand its + or- values. The more throws you have the more expo is required. Full on 45 or more 3D throws usually have 60% expo, or it will be extremely sensitive to fly.


Try this and fly it, then report back