Really all I saw was sneering at my rage with precious few helpful posts. I was raged obviously I am only one who can get mad when something does not work even though there is no apparent reason for it to be broken.
Thanks man that worked. Turns out that DCS world downloaded from origin/steam is different from the ED website one. It is visible from the main menu the steam/origin version lacks module manger and auto-update, also some module icons are missing in the bottom left menu. So when I tried to use the serial from Origin on regular DCS world it did not work but when I put it in Steam activation dialogue it activated without any problems.