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

This Amiroko adapter and a Thunderbolt 3 (USB-C) to USB adapter (see photo) allows you to connect your 2018 MBP to a 30" full-resolution 2560x1600 cinema. You need an Apple Mini DisplayPort for dual-link DVI adapter to interface between the MBP and the 30-inch film display. (See photo. My monitor came with it when I bought it years ago. I'm not sure it always was.) From the Apple Mini DisplayPort to the dual-link DVI adapter, you've got USB and Mini display cable. You connect directly to the 2 MBP Thunderbolt 3 ports via this Amiroko adapter and a Thunderbolt 3 (USB-C) to USB adapter. With this setup you have a full resolution of 2560 x 1600. (See photo)