The OP wants the Strava App on the watch to read HR, along with speed and cadence sensors. From what I read, that’s not possible as Apple Watch does not pair with sensors. iPhone does pair with sensors. However, since the Apple Watch does not broadcast heart rate (like many of the Garmin watches), the iPhone won’t pair with HR from the Apple Watch. Bottom line, at present Apple Watch does not allow the Wahoo Bolt or any device to record heart rate along with cadence and speed sensor data.