App Connect connector: CRM's AppKey is held by RingCentral, not me — what's the right path?

Building an App Connect connector for a CRM that isn’t officially supported yet.

Everything runs end-to-end locally, but I’m stuck on auth.

The API requires an AppKey that’s only been issued to RingCentral, and I’ve been told to go through them to get access.

Has anyone dealt with this kind of setup before?
Is the right move going through their partner program, or is there a lighter path for connector development?

Any insights appreciated.