i should add that i also use a polar heart rate strap. integrates well with rwGPS and mission control, and the data is correct and present when viewed later in strava or etc.I do something similar. I need to track my heart beat, but since I own an Apple Watch didn’t want to get yet another device for that purpose. I finally sprang for the big bucks and got BLEVO which works for it all: bike, heart beat and all. Had to do a kluge to get constant heart monitoring by running Ride With GPS, on the watch though.
If I remember to turn off all the other apps on the phone the battery lasts about 2 to 3 hours. I carry a battery bank just in case. Still too many devices, but . . .
in the end it was not worth the trouble to get the apple watch connected to mission control. hopefully that’ll be improved someday and i can ditch the strap.