“This is not a bug, it’s simply the fact that M1 shares a big part of its architecture with the iPad A14 chip and Apple developers borrowed part of the GPU driver code from the iPad kernel which doesn’t expose an I2C controller (which Lunar needs for DDC requests) and probably never will.”

Developer Alin Panaitiu explains in a different thread that the shortcoming is not a bug and is deliberately added to M1 Macs: For some time now, users with an M1 Mac have been finding themselves unable to control the brightness of third-party displays (using third-party apps) that are not made specifically compatible with Macs.Ī developer of one of those apps-Lunar-said in a Github support thread of MonitorControl, a similar app, that M1 support is unlikely for apps that control brightness on external displays.