What is the best music provider to use with Fenix pro6

You can always go with the 'old way' and transfer music files from your laptop or phone, streaming app is not mandatory. by the way I ever used both Spotify and Deezer and were both ok on my Fenix 6S Pro, thus just chose the one you prefer/fit better in term of specs and plan cost, the plan can be shared with of your other devices. The main issue I've found is the Bluetooth connection stability with pods\headsets of different brands that time to time disconnects during runs, I could live with that but was annoying, for instance when using a Samsung watch the same pods never had any issue.  

Thanks for the reply. Didn't realise you could download straight to the watch. Might give that a go instead.