I left miRack running in the background and locked my screen. It completely drains the battery while backgrounded. Screenshot attached.
There is an Option in the preferences, called „background Audio“. If it is turned on, Audio will be Computed even if miRack is running in the background. Makes total sense for a lot of use cases, live performances ie.
Is ist turned on in your case? If so you can just turn it of, and miRack should be very battery friendly running in the background - without audio of course.