Fitness tracker that streams music over WiFi

[96Firebird]

Right now I have a Fitbit Charge 2, which is a basic fitness tracker that has no music capabilities. At the gym, I use my old gen 2 iPod Touch and stream from Pandora over wifi with it. Problem is, the latest iOS for that is 6.something, and to get any new apps I need at least iOS 10. I now have Spotify Premium and SiriusXM that I want to stream from, but can't with the iPod. My phone is too big to carry around at the gym, so I leave it in the locker room.

I'm looking to get a fitness tracker or smart watch that can stream music from the gym's wifi and connect to my bluetooth headphones. Obviously looking to either stream Spotify or SiriusXM, without needing to be connected to my phone. What are my best options?