Until recently all was fine. Then suddenly Spotify seems to randomly choose whether or not to show my usual three devices (Sonos, Samsung S7, Tesla Model 3). Sonos and S7 are on same network as Windows desktop.
I can play from Spotify Android app to Sonos and to Sonos via Spotify on Sonos app, but not from Windows 10 app.
I notice you've recently had this issue for iOS users. Maybe it's more widespread than that.