I am currently in the same boat as many other out there. No more Nvidia in OS X and no more AMD GPU acceleration for Cycles and now with RTX the difference is even bigger, much bigger. I also bet eevee, which I love working in also works much faster with Nvidia cards.
After more then a decade on Mac I am forced to switch to Windows because of this. There is always Radeon Pro Render but in my case it doesn’t run that much better compared to cycles, especially in viewport.
Blender isn’t the only app that gets a major boost from Nvidia, there are plenty of other apps out there that support CUDA and Optix.
I love MacOS for it’s design and workflow, stability and security. OS and Apps feel like one whereas in Windows it’s spread out everywhere, design and files feel detached.
Both Adobe and Davinci which I also use frequently run fine with Metal support but it’s Blender (amongst other 3D apps) that I want to enhance and that is out of the question.
I was thinking about getting the RX5700XT but that will only help me with eevee if that.
I’m not going to waste 1 hour rendering knowing I could do it in 10 mins. This is my work not a hobby so I have to be efficient.
Windows used to be a Gaming/Office station and Mac the Pro/Art station but nowadays Windows is the Pro/Art/Gaming station and Mac the Office station with a bit of photography/audio on the side.
I feel with the current situation a lot of graphic artists (pro and hobbyists) are going to move to Windows.
It’s a shame that a company can force one into moving away from them while their purpose should be the exact opposite.
Take care lads!