You can't undo hidden hearing loss. You can only stop adding to it.
And here's the part almost nobody knows: your eardrum doesn't block sound, it transmits it.
A thin membrane in front of your ear canal can do the same… like a second eardrum. It lowers the volume but carries the full sound through. Vocals.
Highs. Bass. Same music. Same energy. Just below the level where your ears break.