Are you a trainer? It’s not a required prerequisite for being an SSV but it is recommended and would give you a chance to hone your leadership and coaching skills. If your store is over staffed you could ask your SM if you can train for other stores which would help build your rapport with other baristas and managers in your district. You might need to accept that becoming an SSV may involve transferring to another store as each store can only have a set amount of supervisors. My best advice is to continue to talk to your SM, ask to become a trainer and make a PDP (partner development plan) to focus working on the skills you’ll need to move up. Good luck!