Google at I/O has announced major changes to how apps can access sensor data in the next version of Wear OS (wow! big changes finally!) here, in the Devs insights video. Maybe this can help?
[kind of OT side note]: since in the same video they have announced a collaboration with Sleep Cycle for Wear OS, would you consider a standalone Wear OS app? I think it would be a great addidion, given the great revamp and changes given to the platform.