I'm not sure if Microsoft Edge Insider is supported on Server Core.
I'd be interested to know why you need a browser on your DC though, as the whole point of Server Core is to reduce attack surfaces and encourage good behaviours such as remote administration rather than logging on locally to machines.
I understand how GUI can be dangerous (poor Windows 10 users though...), but anyway it was just a test. so do you think if it wasn't supported on Windows server core then it would at least give me some warning or error message before installing or running? it opened up successfully and i could access the internet, change browser theme etc. but the moment i closed the window, i couldn't find a way to bring it back.
anyway, i found the location: c:\Users\Administrator\AppData\Local\Microsoft\Edge SxS\Application>msedge.exe
I think only the new Microsoft Edge installs in that location, other Windows server programs install in other locations like program files.