When you use "RunAs" what parameters are you using/have you specified?
I've specified the domain, userID and password. It successfully launches in edge with those credentials
Have you tried to run your TestComplete in Administrator mode? So that it has higher permissions than the credentials you have used to launch Edge.
See https://support.smartbear.com/testcomplete/docs/general-info/configuring/testing-under-admin-account.html and https://support.smartbear.com/testcomplete/docs/general-info/configuring/testing-under-user-account.html
