Error 12 on Windows 10 1903, iMac 4K 2017
Win10 1903 can be a blessing or a curse depending on the Mac [firmware]. While I have great luck with 2016 15" MBP, 2018 Mac mini, and 2019 13" MBP I encountered the endless boot loop issue on the 2017 13" MacBook Pro. @dregpu Your 2018 15" MBP can't use the Intel iGPU. It's best to hot-plug the eGPU. For your RTX 2080 Ti issue, download and install DCH drivers rather than the standard drivers to see if that helps.
@itsage Thanks for the tip. I’ll look into the dch drivers. Honestly, there wasn’t a specific reason I needed to upgrade to 1903. I just thought it would be good for security and I hadn’t heard any issues about it. Well, not before I installed it anyway. Is there a link a thread or article as to why 1903 might be better for eGPU’s somewhere?