Somewhere here must lie the cure to tinnitus.

No, tinnitus beyond the cochlea, beyond the hearing nerve even, in some part of the audio processing brain tissue.

Cutting the hearing nerve does not cure tinnitus.

It develops due to a destruction of hearing cells that leads the brain to upregulate gain to catch a weak/absent signal, when the deprivation pattern is just right. (no tinnitus develops when the hearinf nerve is cut -> deprivation pattern matters)