You can submit a feature request on Canny. Keep in mind it’s best if you elaborate in your feature request what the current limitation is with group roles / permissions management and “Set as Group Instance Default” (in-app) that the system doesn’t allow you to do.
Anyone can open instances to private worlds (only visible via direct links) from the VRChat Home website, or self-invite yourself from the VRChat Home website and then open instances in-app using the notification (with appropriate group permissions, if opening instances for a group).
