The Microsoft Windows Store does not require signing applications.
Really? I find that absurd.
Not really, since Microsoft takes take of signing executables.
Google does the same optionally in the Play Store for Android apps.
I snipped your quote because there is no unified process. Someone could make an app for that, but @Sam_Rowlands already goes most of the distance on macOS. The process changes so frequently, I personally think App Wrapper is a charity to us. I feel that anyone who distributes commercially for Mac should buy App Wrapper (within reason).
The rest of it, preparing apps for the app stores, well that’s uh part of my livelihood / business model. Researching these things takes a lot longer than most Xojo users are aware. Excuse me for not documenting it publicly
If you have finished building your app and need to have it professionally prepared for the app stores, it’s one of the services I offer - XojoConsulting.com