Thank you, Traian_Boldea
I’ll check about the Mac sleeping. I had it to not sleep on inactivity, but for some reason there was also a schedule set up to sleep it at night and wake it later in the afternoon. So I disabled that.
I believe the issue of playing for 30 secs must be related to TIDAL. My solution was to sign up for a family account and use a different login just for ROON, so it never plays anywhere else but through ROON. So far (after 24 hours) this seems to do it.
I really think TIDAL sometimes thinks it’s playing (on my iPhone or in a web browser) even though it’s actually stopped. That’s a bit of a problem, if you don’t want to pay for extra subscriptions.