arduino mega 2560 serial problem

hi, i am working on a project that is an auto pilot for a glider, and i am having problems with the gps , the arduino cant read the data, wiring is ok, tested with the library example and works, but when i add start to add the other devices it randomly reads the data and most of the times fails to parse new gps data, i had copy the library example and didnt modify almost anything sustancial.
My hardware is
wavesshare 11 dof imu mpu9255 and a bmp280
adafruit gps v3
mpx70002vd
sharp dust sensor GP2Y1010AU0F

heres the code, i am suspecting that some library timer or interrupt that i cannot see from the code is messing with the serial port3, also tried to use a software serial and other pin and the same problem, thinking to switch to a I2C gps or a serial to I2C converter

Advanced_I2C2.ino (20.8 KB)