It probably won't help but just FYI - it's possible to turn on / off HDMI outputs on RPi 4B:
HDMI display_power ON ALL HDMI ports:
vcgencmd display_power 1
HDMI display_power OFF ALL HDMI ports:
vcgencmd display_power 0
HDMI display_power ON HDMI port 0:
vcgencmd display_power 1 2
HDMI display_power OFF HDMI port 0:
vcgencmd display_power 0 2
HDMI display_power ON HDMI port 1:
vcgencmd display_power 1 7
HDMI display_power OFF HDMI port 1:
vcgencmd display_power 0 7
HDMI ports connection status:
cat /sys/class/drm/card0/*HDMI*/status
Also regarding to HDMI devices (re)detection just stopping / starting Kodi should be enough, it also take long time but it's still more quick than whole LE reboot.
systemctl stop kodi
systemctl start kodi
(or systemctl restart kodi)