Some resources about external GPU support that might be relevant:
The Beginner’s eGPU Setup Guide for Mac:
https://egpu.io/setup-guide-external-graphics-card-mac/ [egpu.io]
External graphics cards work with all Thunderbolt-equipped Macs. A 2011 MacBook Pro with the first generation Thunderbolt and the latest 2017 MacBook Pro with Thunderbolt 3 can both harvest the power of an eGPU.
MacBookPro eGPU - Unboxing / Setup / Test in FCPX / AMD Radeon RX 570 8GB:
https://www.youtube.com/watch?v=FLLGuO64UUQ [www.youtube.com]
MacBook Gaming Still Sucks - GTX 1080 + macOS:
https://www.youtube.com/watch?v=-DaDjFm7_qw [www.youtube.com]