Exactly the same problem connecting my LG 34WK95U.
Mac Mini 2018 -> eGPU (Thunderbolt 3) -> LG 34WK95U (also Thunderbolt 3), monitor wakes up, stays black, after few second "no signal" and then turning on power saving mode.
Unplugging and replugging the thunderbolt in the eGPU most of the times restores my connection. After every reboot I need to perform the again. Coming out of sleep mode works OK.
When I connect my Mac mini directly to my monitor it works OK.
So conclusion is that it must have something to do with how the eGPU initializes the monitor, or the way macOS loads drivers.
I do hope that BlackMagicDesign and Apple are giving top priority in fixing this. Many reports on the internet about similar problems. One of them said that Apple was aware of the problem and working own a fix.
A true shame this setup is not working.
Best wishes from The Netherlands.
neosolyt wrote:Same problem here:
Mac Mini (2018) > eGPU > LG 34UC99-W via USB-C doesn't work properly.
However, I made it work SOMETIMES by unplugging and plugging the USB-C cable. But every restart is leading to the same problem: Black Screen
Such a shame...
Will this setup ever work? Are there updates in this regard in (probably near) future?
With best wishes for a Merry Christmas and a Happy New Year from Germany.