W10S and Browsers

So we have Chrome on iOS which is not Chrome but in fact the Safari browser engine and Google has built its own browser user interface for that connects to Google services but its still running the same code as Safari.

We have Edge, Firefox and other browsers on Android that are in fact built on Google’s Chrome engine.

Why can’t Google build Chrome UI on the Edge engine? Is Microsoft locking it down not allowing third parties to customize their own Edge engine user interface? Are is Google just trying to kill Windows 10 S for Android or Chrome Devices. Could it be that Edge is still too new for Google to do this and they want to but Microsoft is keeping W10S so locked down and crippled because of Edge’s youth and underdevelopment? Why can’t Google’s engine be allowed into W10S? Ok W10S is so new I get “why build an app for it no one knows if the W10S it will gain traction and survive. I get that too but why not put your app in the Microsoft Store? Does Microsoft charge for “free” app? Why isn’t Chrome (todays version) not in the Microsoft Store for standard W10 Home and W10 Pro? Would it not be safer coming from the store?

To me the optics looks like Microsoft is trying to bring its services to everyone’s platform Edge, Outlook, Office, OneDrive, Cortana and yet everyone is doing their best to not return the favor. Is it just optics? I do see that you cant have Google’s assistant, Alexa or even Siri replace Cortana on W10.

I know I am answering my own questions a bit here but I would like analysis form smarter people.