There is definitely no short circuit and other problems with the power supply. I have previously used Raspberry PI OS and everything was fine. The red background on Kodi appears at random moments. Depending on the connection and disconnection of various add-ons. I don't notice any devices.
Only the keyboard and monitor from the PC via hdmi are connected to the Raspberry.
Hi, I'm using 2 RPi3 with LibreElec (was 3, one I replaced with RPi4 recently) for years and didn't noticed any similar issue, even when had power source issue. And I didn't know to exist any "recovery mode" for RPi3 version of LE. Did you installed to SD card using the "LibreELEC USB-SD Creator"? A fresh install, without any addon, could be done, better if you have an another SD card to exclude the card issue too...
About the power source, if you can to try with another, just to be sure is OK... Try to change the USB (power) cable too, a short cable is better.