So you used the “Tags from file names” function to read the tags from the file name sructure, right?
To me this looks like your files had title, album name and artist as part of the name, and with
%tracknumber% %title% you read this all into the title tag. With the already tagged files this will be difficult to remove, as there is nothing delimiting the individual parts and it is unclear what belongs to the track title, album title or artist.
Best would be if you hopefully still have a backup of your files and process them again. If you can share the folder and file structure we could help coming up with the proper pattern for “Tags from filenames”.
If you don’t have a backup it gets more difficult. Are album and artist still tags still present in the files? You could add a script like this in Options > Scripting:
That script would attempt to replace “Artist Album” from the track title. That requires that the spelling in the artist and album tag is exactly the same as it is now in the title. Add this as a new script, give it a nice name (“Remove artist + album from title”), but keep the script disabled. Then load your files and run the script manually via right click context menu → Run scripts. It might not work in all cases, but maybe it cleans things up enough. Check the results before you save.
Another way out would be to actually tag all your files against MusicBrainz data. But I understand the only thing you wanted to do is the compilation flag, right?
One thing I noticed in your screenshot is that
%TCMP% is not a variable name known to Picard and hence this won’t do what you expect (it would add a custom tag called “TCMP”). The proper variable for the compilation flag would be
%compilation%, and it would be expected to be set to “1” for compilations and “0” or not set at all otherwise. Not sure about your folder structure, but your attempt to fill this from the folder structure indicates you have this info as a folder. But probably that folder name is not “1”, or is it?