Watch Siri overriding my requests

If I ask Siri to play music whilst wearing the apple watch it will play Apple Music even though the default is YouTube Music. If I ask iPhone Siri, it will play YouTube Music. How do I fix this? It's annoying when my phone is in my pocket, my headphones are only connected to my phone, and the Apple Watch overrides my request.

*I have YouTube installed on the watch, which is tethered to the phone. All presets and permissions seem to be correct on the iPhone.