Thanks for the information. It's curious because the Mac launcher actually says that it will only enable HDR on MacOS 10.14.2 or higher, implying that the game will run on Mojave. Guess it's a red herring.
I find myself in this situation fairly often because for some reason, Mac game publishers seem to think it necessary to restrict the OS to latest and greatest version available at game release. It seems completely unnecessary, because many of these games are years-old ports of console and PC games that don't need the latest tech.
There are ways to get Catalina running on my old Mac, but they involve moving outside of what Apple will support, and even into 'Hackintosh' territory in some cases. I'd rather avoid that, but if Larian and Apple insist on the shiniest OS version. Catch-22 I guess. But Apple can forget about me buying a new Mac Pro. Those things are insanely expensive.
