So it begins - CES 2025 started and Garmin released the HRM 200 which operates by default in open mode, but one can switch to a secured pair mode over Bluetooth. see https://www.dcrainmaker.com/2025/01/garmin-hrm-depth-review....

Another tweak to the Garmin HRM design is conforming to laws in Australia and USA for requiring a tool to access coin cell battery compartments. But the required tool is built into the HRM strap.