Yes, I'm using one of those adapters as well right now. They work just fine. The problem for me is that I don't see the boot screen through that adapter. If I have my LED Cinema Display connected to the DisplayPort instead I can see the boot screen (but then the screen goes black when Catalina boots up).I have a GTX680 flashed with a Mac ROM to support EFI and an Apple boot screen. It is working fine in both Mohave and Catalina. I haven't used Display Port in a while (I was having some issues with my DP to miniDP adapter) but am now using an HDMI to miniDP adapter to drive my Apple Cinema Display.