Firstly, I think you have not done an autotune to your 20" propeller quaddrone and Harmonic Notch filter yet.
how do you derive the following?
ATC_ANG_PIT_P,6
ATC_ANG_RLL_P,6
ATC_ANG_YAW_P,6
Keep these to the default first. you may need to change later for a big drone.
PSC_POSXY_P,1
PSC_VELXY_D,0.5
PSC_VELXY_I,1
PSC_VELXY_P,2
MOT_PWM_TYPE,7 DShot1200, do you think you may have connected it wrongly? SERVO1_FUNCTION,34 (should SERVO9_FUNCTION,33, digital ESC)
FRAME_CLASS,1 Quad
FRAME_TYPE,1 X
according to the tunning guide you have to complete the tune in sequence
angle rate - the inner most control loop
angle - the second control loop, wraps around the angle rate control loop
Loiter adds a 3rd cascading outer PID control loop on top for position. And the inner angle and angle rate loops are still used.
To improve the loiter response, you first need to make sure the innermost angle rate control loop is performing correctly, after that the second level angle control loop is doing OK. And only after that you tune the outermost position control loop.
for big drones after autotune and Alt-hold flying is good, then you can check this post. importantly, you must have a low noise and vibration drone before you start the autotune. your current vibration is a bit high, try to aim for 15 m/s/s max.