Started my server from scratch on a different PC - library language mixed up now

Hi,

I moved my Plex media HDD to a new PC and will be running the PC only for Plex now.

At first I moved the old Plex database files to the new PC, but I had a lot of problems watching certain movies. They wouldn’t load for some reason. I reinstalled plex to start from scratch then and now I got movie library which is mixed up in languages. All my movies are German - the library language is set to German, but many movies are with English title and German cover now. I don’t know why that would happen. I also checked if the filenames are the English titles but they aren’t (some are, but they still got named with the German title in plex).

How can I fix this now? I updated the libraries, optimised the database and updated the library again - nothing changed. Please help me!

edit: sorry if this is the wrong category to post this!