if you can't access the batocera menu via start, connect to batocera via ssh or the network shares
and edit recalbox.config to set global.videooutput=
Correct values can be found via:
/recalbox/scripts/recalbox-config.sh lsoutputs
for example, on my computer:
eDP1
HDMI1
eDP is for laptot screen.
HDMI for hdmi output.
VGA for vga output.