

It would be awesome if Polar was supported by GadgetBridge, because then you could have fully offline and private control of the device.
GB recently got Garmin support and it’s pretty solid. I switched from the Garmin app to GB exclusively and haven’t lost really any features. Besides the social networking, but that omission is a feature, not a bug.
If it’s really 3rd party friendly, I wonder how easy it would be to get support.
Don’t have a good rec to add to the discussion of hardware, but I would love to give a shoutout to GadgetBridge, which is an Open Source Android app that is a vendorless alternative to controlling lots of smart wearables (and other gadgets). It doesn’t currently have Polar support, but seems that might be fairly easy to implement, since polar publishes their SDK online (and presumably the protocol with which it communicates).