I have tried to transfer my working database from my old win 10 laptop to a new win 11 laptop.
I first copied over data using %appdata% [using copy/paste via usb ]to new laptop.
I then installed latest version of libreoffice on to the new laptop, then tried to access one of the backup files in appdata, but all though the forms and queries are all there, the tables were blank.
I then tried to copy the old database files that i found in the user directory to the new pc, but again all I got is blank tables.
Which database did you use? If you have used internal databases the data are saved inside the *.odb-file.
Open such a file and have a look at the bottom of the file in status bar. For an embedded database you could read
Embedded Database → Embedded HSQLDB
or
Embedded Database → Firebird (embedded)