how long is your music playing for when you test this? the Sonos integration only updates ST with status every few minutes, it might even be 5 I forget. But if you add an app such as “Big Talker” it updates ST with the Sonos status every minute.
I use resume music and it works well for me. Occasionally if I have back to back notifications come through, it will start music when none was playing before. This happens because when the first notification is playing, ST gets updated with a playing status. Then the second notification comes through and it “resumes” playing status from the first notification.