I have change the parameters you show me but there's no modification.
Is there another solution to change the "AUTOMATIC 2D OVERVIEW" altitude zoom and distance before next direction?
I've seen it in your sys.txt :
2dheadup=1 ;(1) ;( extra 2d heading/north) ;bird's eye view 2D view you can switch off the automatic switch from 3D to 2D in the sys.txt; (0) not change, (1) Switch
north_up=1
Is it this fonction?