Assuming an apt-get installed or openHABian install, the files are located in /opt/openhab2/userdata/jsondb.
Also assuming that these files haven’t become corrupted you can copy them all over. If they have become corrupted, you will find backups in the backup folder and you can use one of those sets of files.
That’s for that Rich most of my system is up and running again now started with the fresh 2.3 install copyed Jasondb files over and conf folder still got a few problems will work on them some more