[FIXED] Problem: Can't open unsafe ports on Edge insider

Solution:

1) Disable all the features that exist within "Edge Settings > System and Performance" of Microsoft Edge (eg. Efficiency mode, Save resources with sleeping tabs, etc.) and then after closing the browser Microsoft Edge, no more edge instances will be running on the background.

That means that the described solution on this thread can work:

2) Microsoft edge app --> right click --> properties --> shortcut tab --> Target
And there add the desired port (you want to forward) like below:
"C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe" --explicitly-allowed-ports=10080