Fanart etc in centralized folder

I realize I might be countercurrent since I can only find posts about people who want to do the opposite, but: some time ago I moved from kodibuntu to libreelec and I now have fanart, posters and nfo files plaguing my movies folders on the network instead of being centralized on the ssd I bought exactly for that kind of stuff. It’s possible that this happened when I restored the backup from kodibuntu, because I don’t see this happening for the new movies being added.

Now I have two questions:

In which xml and how to tell Kodi to only store nfo, fanart and posters in a specific folder as kodibuntu was doing.

How to correctly cleanup the mess I have now. I could just delete all nfo, fanart and posters but I’m afraid the are referenced in some table in the library db. I can manage that, but I don’t know in which tables these references might be.