I find differences every now and then but don't make a list of them.
I know the BB Plugin is identical for Mac/Win and can be easily compiled to Mac or Win. I don't know if it's because the programming they use for Biab as they are both programmed at different times, I think most crossplatform DAW's are the same and released at the same time.
I'm sure with the 2021 release there will be more Win features added.
If you do a basic crossgrade of the app only you can use your Win RealTracks directly if you have the wav version or convert the wma to wav or m4a.
I have the Mac app and just use my Win Audiophile drive with it.