cesartaqui I think you might be able to do something like that in batocera.conf once you open it at the bottom you will see:
# ------------ I - EMULATORS CHOICES ----------- #
## You can override the global configuration here
## Here is the snes example
#snes.videomode=CEA 4 HDMI
#snes.core=snes9x_next
#snes.shaders=/userdata/shaders/shaders_glsl/mysnesshader.gplsp
#snes.ratio=16/9
#snes.smooth=0
#snes.rewind=1
#snes.autosave=0
#snes.emulator=libretro
#snes.integerscale=0
Or via Xrandr: “Display issues, where xrandr is your friend”. But Xrandr will change entire Batocera resolution.
You might want to play with emulator options. Somewhere in submenus of Batocera thare is ‘per system config’.