Hello, sorry if posting in 2 different languages and 2 different sections was considered spam. Having had no answer in the French section of the forum I allowed myself to repost in the English section of the forum. I wouldn't do it again ...
I tested all the different video modes and for those who still leave me a display, the problem remains the same. I tested with another pi 4 and the problem remains unchanged.
On the other hand I still had a pi3 and I installed the last compatible version for pi3 via pi imager (same installation procedure as with pi4) and I plug it all into the same screen, with the same adapter vga / hdmi and no display issues. Everything works normally ...
Is there any configuration other than video mode on the pi4 that sets it apart from the pi 3?
Thank you in advance,