I have an older iPad mini for this purpose (but an old iPhone without a data plan would work too). I setup a separate home@<domain> iCloud account under my family plan and use it exclusively for streaming music vi AirPlay, cooking w/ recipes on Paprika, HomeKit controls, reminders, timers, etc. - no Slack notifications, no calls, no calendar reminders. The AppleTV goes on the same account too. It's really been a great solution.