Would it be possible to use only external gps/compass and disable all internal gyro/imu?

[dkemxr (Dave)]

Use the search function here for “external IMU”.

[Flyhigh]

Lol gee thanks Dave lol

[Yuri_Rage]

Your condescension is duly noted.

Here’s a related thread:
How to use external imus? - ArduPlane - ArduPilot Discourse

Good luck.