Review on Amiroko USB-C to Mini DisplayPort Adapter - 4K/1080P Support for MacBook Pro and Alienware, Silver by Charlie Dillon

I don't have this adapter that works with two computers running Big Sur. Reviewers in 2018 and 2019 reported success with earlier versions of the operating system. Must be Big Sur's fault. I know the monitor and display adapter work fine because I've used them for years with my iMac (27" Mid 2011) running 10.13. 6. MONITOR: Cinema Display (30 inch DVI (Late 2005) (M9179LL/A) DVI- to-MDP: Apple Mini DisplayPort to Dual Link DVI Adapter (model A1306) upgradeed to iMac (Retina 5K, 27", 2020) running Big Sur 11.4. See photo for an example of an unusable video display. Also tried on a MacBook Pro (13" 2017, four Thunderbolt 3 ports). Same result. Sometimes the Cinema Display is not noticed. Sometimes the power light comes on and then goes off again (and changes). Dual link DVI adapter + DVI adapter MDP cable connected to an Amiroko adapter (this product) that was connected to an iMac USB-C+ port DVI adapter USB cable connected with the following options: ++ (iMac) USB Type A port++ (iMac) USB Type A port on an external USB hub (connected to iMac Type A port)++ (iMac) USB Type A to USB C adapter to USB C++ port (MacBook Pro) as above as it has no Type A ports