I have 2018 mac mini, and I connect my 4k monitor to hdmi port and the other monitor with the usb c digital av multiport adapter. Every time I reboot my computer only one monitor is detected.
Mac mini 2018 or later
Try putting them both on the Thunderbolt 3 (USB-C) ports, one on bus 0 and one on bus 1.
see > Connect multiple displays to your Mac mini (2018) - Apple Support
Try putting them both on the Thunderbolt 3 (USB-C) ports, one on bus 0 and one on bus 1.
see > Connect multiple displays to your Mac mini (2018) - Apple Support
Hello,
Try updating to macOS 10.15.5 to see if it resolves your problem.
System Preferences > Software Update
not detecting two monitors after reboot
