While the academic exercise of keeping track of the differences between PhotoLab Mac version and Windows version is useful, trying to make the two apps identical will just make both of them worse.
Why?
It would mean sacrificing both the Mac only features and the Windows only features. Most of these features are on their respective platform as the underlying OS and SDK make them easy. They aren’t on the other platform as either OS or SDK on that OS make them hard.
Moreover, I don’t believe there’s many users out there any more switching between Mac and Windows to run PhotoLab.
That said, where possible, maintaining feature parity is great. I’d sure hate to lose the easy wins on macOS (like split-screen compare, advanced history) and I’m sure the Windows users would hate to lose the file management available on Windows version as well as the compare two images functionality.
Because macOS and the SDK are very different than the Windows one. This kind of file and folder management one receives for more or less free in the Windows environment and making it work on macOS is more work.