I'll agree that a test file, a file that is identical in sketch & figma would be an interesting way to see which is better performance wise. Now, how do we determine what is "big project" though. What that "big project" needs to utilize that gets both tools to the limits.
This is quite random since a file would have to be made specifically on each platform. The reason is that Sketch is coming with a external library feature like Figma and at the moment, there is no way to import Sketch with included libraries in Figma yet since it is quite new…!
I'll agree that a test file, a file that is identical in sketch & figma would be an interesting way to see which is better performance wise. Now, how do we determine what is "big project" though. What that "big project" needs to utilize that gets both tools to the limits.