This is definitely a known issue on 2012/14 the Mac Minis (USB 3.0). https://support.apple.com/en-us/HT203729 https://support.apple.com/en-us/HT203729 https:/

This is definitely a known issue on 2012/14 the Mac Minis (USB 3.0). https://support.apple.com/en-us/HT203729 https://support.apple.com/en-us/HT203729 https://forums.macrumors.com/threads/usb-3-causing-interference-with-bluetooth.1696604/ https://forums.macrumors.com/threads/usb-3-causing-interfere... Apple's article mentions USB 3 devices, but the issue is very much with Mac Mini's ports. Moving the devices further away doesn't help much. I have a pair of cheap Bluetooth earbuds. They have a range of about 30 feet with when paired with an iPhone and about 4 feet when paired with the Mini. Apple's Magic Mouse needs to be within about 4 feet to work as well.