To play music from the YouTube Music app on the watch without using your phone, you need a Bluetooth-enabled version of the watch, which is not the case with your WLAN-only model. However, you can download tracks to the watch using other methods, such as transferring music files from your phone using the Galaxy Wearable application. To use YouTube Music without a phone, a Bluetooth connection is usually required to listen to music on headphones.

If you want to run without your phone, you can consider transferring music files directly to the watch via the Galaxy Wearable app, but this won't work with YouTube Music without Bluetooth.