According to your log Emby starts and uses Mono 109 from LibreELEC.
The log however shows that Emby fails to find directories in /media.
Have you rebooted your system and checked the state of /media?
Yes, my Internet Box lost its Hard Drive too, at the same time (all the errors in the logfile are linked to the mounts not accessible anymore).
My provider will need to replace it very soon.
Do you think these paths that are not accessible anymore could cause Emby or Mono to restart itself every 2 minutes ? (or it's just another problem)