It's possible that the RPi2b is still more prone to SDcard corruption than the newer RPi 3 and 4 devices.
You can try re-imaging the current SD card, which may result in a similar result over time.
Or use another SD card and try that.
It's also important to keep the bootloader updated as there're several fixes regarding to SD card.
rpi-eeprom/release-notes.md at master · raspberrypi/rpi-eeprom · GitHub
There's an example how to easily upgrade the bootloader to latest one:
RE: Is it possible already to set up a rpi4 with kernel 5.4?
Also make sure you don't use any suspicious / banned add-ons which seems to be the quite often reason of such issues.
See here: Official:Forum rules/Banned add-ons - Official Kodi Wiki
Edit - Arghh, sorry - I have overlooked it's RPi 2B so my post is a bit irrelevant regarding to bootloader update (which is valid for RPi 4B)... 
ghtester We're not talking about the RPi4 here, so your links are a bit off-topic... 
Klojum OK, you are right - my fault, sorry, I have overlooked it... 
It looks, for some unknown reason, I have focused more to your post #2 and "4 devices" mentioned than to original subject...
But how can i preserve all my settings, add-ons, media db? Should i backup .kodi folder for that?
There's a backup option in Kodi - see menu Settings - LibreELEC - System - Backup
I'm stating the obvious here, but make sure to afterwards move the backup tar file to a safe location on a different storage device. 
There's a backup option in Kodi - see menu Settings - LibreELEC - System - Backup
Kodi won't start, as i mentioned before
I've reimaged my sd and now kodi working. I copied .kodi folder before. Should i copy it back?
Well, I thought this question was about a backup of further working / fresh LE installation as from my point of view it's too late to try backup a corrupted installation and .kodi folder might not be enough.
By using a search, you may find something like this: Basic backup/restore question
I copied .kodi folder before.
Next time also do the .config and .cache folders if you want to be complete.
