I'm using the original Raspberry Pi (that's a '1', right?) and experience the same thing with both 9.2.1 and 9.2.3, which I'm loading on my SD card with LibreELEC USB-SD Creator:
after the initial boot, where it appears to be resizing the partition, etc. it reboots itself. So far this sounds like the expected behavior. Upon the second boot (performed automatically), it gets to a display of the Kodi 18.6 (Leia) screen, but then goes black after 5 or 10 seconds.
I've searched a bit for this problem, but don't see anything, so I'm asking the community. Until the black screen, the video output looks perfect.
If this were due to a wrong resolution, I wouldn't expect the initial Kodi image to appear. Unless it's switching resolutions? That's as far as my knowledge/logic take me.
How can I troubleshoot this?