Hopefully you can fix this one. The gamepass version of Fallout 76 is fully able to be modded, but has a different .exe name from the Steam version. As a result when you try to manage the game in Vortex, it fails to detect. By default (and in the steam version) Vortex expects to find Fallout76.exe. In the gamepass version, the main executable is Project76_GamePass.exe. Beyond that the data subfolder structure and ini file location are the same, so it should just be a question of allowing a different executable name to be detected.