After a little bit testing I saw that my sceneries worked by hazard. That means when I start FSX sometimes I see buildings and sometimes I don’t see buildings. Every time the sceneries didn’t work, I don’t found the “couatl powered products” in the Add-on Menu but the “Add-on Manger “ is visible (also when there are no buildings)
I also checked the simconnect.ini (see attachment).
It's not clear, from your message, if when you see the Couatl.exe loading in simconnect.ini, you don't see its menu.
Because, one thing is that Couatl is not loading, which is the problem others have, which is always related to antivirus (if the antivirus is blocking it, it will NOT load) or problem with Windows trusting mechanism, but it's an entirely different thing, if Couatl IS loading, but you don't see its menu.
So, if your situation is that Couatl is loading, but you don't see its menu, it's an entirely different problem that others had, and doesn't have anything to do with antivirus or reinstalling. Instead, something else is happening.
First, check if you have a Couatl.err file in your %APPDATA%\Virtuali folder. If you have it, please post its content.