Can emulationstation only be displayed on the standart video outputs of the RPi?
Yes. I have no problems with using the composite video output. I have an old television I saved from a dumpster that I use composite video for. No issues.
You may need to force the video output to composite, though since you see the boot screen, it shouldn’t, but maybe it is trying to send the output to HDMI after it loads.
sudo raspi-config --> Advanced Settings --> force composite output