No, the watch is not a music player, not to mention Spotify connect (it doesn't have a mobile data line either).
However, the Fenix can control the music on your mobile phone via the "music control widget".
So you could play the music with the Spotify app from the mobile phone to the Bluetooth headphones, put the mobile phone in your pocket and control the music on the mobile phone with the Fenix.
In practice, however, I see this less... During sports, it's relatively awkward to switch from a running sports app to the music control widget, and I don't see any real added value in everyday life.

No. The watch is mainly used for independent recording and display of fitness data, but can be used to display data and remotely control apps in connection with the phone (e.g. notifications, e.g. show Whatsapp messages, show accept/reject phone call, show map, etc). You can find an overview of apps here: https://apps.garmin.com/de-CH...

This watch is first and foremost a sports watch with lots of functions for all kinds of sports and the nice bonus that it is also a smartwatch. However, if you are primarily looking for a smartwatch, you will certainly not be happy here, although it does have quite a few features - in my opinion :-)