when I changed the resolution from within Kodi to 1024×768, for speed in Kodi itself, it all works ok. then i went back to batocera/emulationstation menu by exiting kodi, the screen is only partial visible, that is batocera is rendering in the original resolution 1920×1080 (as previous) on 1024×768, so the right and bottom part of the es video output is not visible (outside of borders).
luckily the es/batocera menu itself (hotkey) is usable and just barely fits on the screen.
so, there has to be a videomode change back to 1920×1080 res when exiting kodi.
also - kodi does NOT save the set videomode (i changed to 1024×768, but after shutdown,
its back at 1920×1080).