JBL UA project Rock headphones

Hello everyone,
I recently picked up a pair of lightly used UA project rock headphones and they aren’t very loud at max volume.
I can’t connect them in the JBL headphone app, the app doesn’t recognize them… and when I install the equalizer app and they can be much louder, but the sound is more lossy.
I have a feeling that it won’t be as loud as it should be without the app, as if they are running in some kind of safe mode without the app.
What i can do to make them laider, is there some other app?