My goal was for the electronics portion of the bracelet to be small - like 10 x 20 mm.... unfortunately, the haptic motor requirements mean that I need a larger battery - making my design - best case - 15mm x 35mm.
Given that, I'm rethinking my stance on connectivity. I originally planned to build a second charging station that would also send data (via wifi or ble) to the cloud (where it could be analyzed and reported back to the user).
Since I need more space, I may include BLE functionality within the bracelet. This would make data sync easier (meaning my charging station would only need to handle charging).
Something like the nRF52840 (or the nRF52832) looks promising: small, a full SoC, has RTC functionality, and can operate between 1.7 and 5.5 V (which might mean removing the voltage regulator).