I'm having a similar issue with 9.1.501 in a RaspberryPi 3B. If I set sdtv_mode=2 on the config.txt I get the "LibreELEC" splash screen, but never see the Kodi splash screen or the UI. SSH is available and I can edit the config.txt.
If I set sdtv_mode=0 or comment out the sdtv_mode line, I see Kodi's splash screen and interface, but mode is set at 720x480@60Hz (thankfully this CRT is PAL, but multisystem on some inputs).
Going back to 9.0.2 runs into the bug where screen overscan compensation ("video calibration") is lost after reboot (that's why I was trying 9.1.501).
Going back to 8.2.5 leaves some addons not working.
I don't think it's a bootloop because I only see the LibreELEC myprepaidbalance splash screen once and the SSH connection doesn't drop. Sorry I can't provide a log right now; what information do you need and how do I get it?
Thank you for posting something like this