Lots of small issues

It should not take so long to get to 100% throttle. It should be like 15 seconds max. Real planes take off at 100% throttle, not 1%.
I think it’s treating throttle as a velocity rather than forward force.
I think it’s treating gravity as a velocity rather than a downward force.
The plane should be able to pitch/roll 360 and should not auto level.
Pitch follows the axis of the earth rather than the axis of the plane.

The plane should start to drop out of the sky when rolled 90 degrees due to the lack of lift/drag fighting gravity.

I think overall if you just add basic physics and aerodynamics equations that simulate real life, it would be a much better simulation and more fun to fly.