We want to test our 3D model based website with playwright but there was an idea that we shouldn't even need to test it on macOS, if there is no difference between the 2 platforms, and there is bigger differences between webkit or chromium, but webkit can be also tested on Windows.
It's different.
WebKit on macOS is native, like Safari, while on Windows/Linux, it's a custom build by the Playwright TeaТm.
GPU acceleration - Metal on macOS and DirectX on Windows.
Different font renderings and UI. Screenshot from Mac won't match one from Windows.
https://playwright.dev/docs/browsers#webkit
I'd say that if you use WebGL, Three.js, etc., it'd be nice to test it before moving all tests to Windows, just because of 3D models.