Not sure if this will work in your framework, but you’ve surprised me in the past. On Android, when you swipe from the top you get the notification list. At the top of the list is the current audio with some basic controls - pause, next, etc. On the latest build you can even scroll to other recently active sources. NPR → Tidal → Libby for example. It would be great to have Strum Machine in there as well.
Why? I can be reading lyrics on one app and pause Strum Machine playback quickly since I dont have to change apps.