How to resolve Spotify playback problems on Apple Watch Series 8?

I've been using Spotify on my Apple Watch 8 for some years now, but problems remain, resp. come and go. While I usually only use Spotify via my watch to listen to music while running, once in while I listen to content via my iPhone. But every time I do that, it is hard to reconnect back to the watch.

Right now, although everything seems set, I hear nothing: iPods are connected to watch, playlist is running, song is showing to run - but there is no sound, and control is partly frozen, meaning, I cannot hit pause or skip buttons. Any idea on that?

-- There is always some new problem with apple watch and Spotify and it drives me nuts. (for various reasons I won't switch to apple music.)

[Re-Titled by Moderator]

Original Title: Spotify on Apple watch, no sound in spite of connection