Look at filament unload rate
From the blog
Hey eric thanks for the work you have done on this firmware couple of things i have noticed
really the only main one anyhow is the stock filament load and unload is set at like 400+ mm at about 40mm/s (cant recall actual values) but ungodly high you may what to update that in your config
found this to be more suiting and not filament chewy
#define FILAMENT_CHANGE_UNLOAD_FEEDRATE 10 // (mm/s) Unload filament feedrate. This can be pretty fast.
#define FILAMENT_CHANGE_UNLOAD_ACCEL 20 // (mm/s^2) Lower acceleration may allow a faster feedrate.
#define FILAMENT_CHANGE_UNLOAD_LENGTH 10 // (mm) The length of filament for a complete unload.
// For Bowden, the full length of the tube and nozzle.
// For direct drive, the full length of the nozzle.
// Set to 0 for manual unloading.
#define FILAMENT_CHANGE_SLOW_LOAD_FEEDRATE 6 // (mm/s) Slow move when starting load.
#define FILAMENT_CHANGE_SLOW_LOAD_LENGTH 0 // (mm) Slow length, to allow time to insert material.
// 0 to disable start loading and skip to fast load only
#define FILAMENT_CHANGE_FAST_LOAD_FEEDRATE 10 // (mm/s) Load filament feedrate. This can be pretty fast.
#define FILAMENT_CHANGE_FAST_LOAD_ACCEL 15 // (mm/s^2) Lower acceleration may allow a faster feedrate.
#define FILAMENT_CHANGE_FAST_LOAD_LENGTH 20 // (mm) Load length of filament, from extruder gear to nozzle.