I have not found a way to disable native power. I am using a HRM-pro (do not plan to buy/use another HR-belt) and do not want to collect garmin power as I am using Stryd for running power (and have been for several years). Stryd, IMHO, is way better correlated to effort/RPE. Have I missed something?
Having both messes things up as they are very different. I can manually edit the FIT file and remove a data field but that is very cumbersome if you run 5-7 times a week...