What you write should work. I understand you have Folders with presets in your User folder, and that all your ressources is located on the path that's set in ASC.
However - if you have many thoudsands of presets, then it can take quite some time for the database to build, when you open the application. Also the database might be damaged. You can try to delete the db.db3 database file in the main Preset folder. Then open the application and give the databse some time to build. You should be able to sometimes see the number of preset change while the database build.
I have imported and organized MANY .sysex files for dx7, So before I did a format/reinstall of windows recently I made sure to back up all my folders from Arturia\Presets\DX7 V\User ... however I'm sad to see that none of them show up any more. How do you get placed presets to show up without using the import feature?