This has been broken since Monterrey macOS 12.0. I am running an x64 app under Rosetta2, and trying to test ProMotion. Is this possibly fixed in macOS 14.0? I see mention of a universal CAMetalDisplayLink finally, so we can also try that, but it won't fix testing on older macOS.
https://developer.apple.com/forums/thread/701855?answerId=708409022#708409022