Hi Umberto,
I dowloaded the standalone version of Add-On Manager but I cannot get it to work. After initializing it starts to mention that GSX level-2 is required for: LAX, LAS, MEM, JFK V2, HOU, CLT, SDF and GVA.
Then I get an error code: 1073740791.
Coatl engine cannot run because AV firewall preventing it.
I disabled Windows Defender and Kaspersky before downloading and during installation. Even went to Kaspersky to confirm programs as trusted but still no joy!