Today I setup my new M1 Mac mini with a 1TB SSD and 16GB of memory then braced myself for Bluetooth, display, and wake from sleep problems I’ve been reading about. My Mini is connected to a Dell 34” curved monitor set at 3440x1440 native resolution and 60hz refresh rate using the HDMI to HDMI cable that came with the monitor. Display sleep is set to Never and Prevent your Mac from automatically sleeping is NOT checked. The Dell monitor is NOT 4K. Apple Magic Keyboard 2 and Magic Trackpad 2 are paired via Bluetooth. Most preferences in System Preferences were left on as default and only settings that were not needed were turned off. The only peripheral attached to the Mini is the Satechi USB-C Stand & Hub with SSD Enclosure. Then it hit. My Mini experienced the dreaded display flickering after wake from sleep. To solved the problem the Mini was shutdown, disconnected the HDMI to HDMI cable that came with the monitor, got a different cable, a new Uni USB-C to DisplayPort cable to reconnect the Dell monitor, then booted the Mini. The flickering stopped. As a test I put the Mini to sleep for several hours, woke up and restarted it several times with no display flickering. So far no Bluetooth or any other wake from sleep issue has happened. Fingers crossed.
