The high-level summary I would give of this is simple. If you like Project Wingman and want to be able to mod your game without limits or hacks buy it on Steam or GOG.
The Microsoft Store is really not designed for modding, most modders won't be able to help you with issues and most modding tools aren't designed for the Store version, if they work at all.
Contrary to popular belief, not all game stores are equal. The Microsoft Store is highly opinionated on how it installs apps of any sort including games from Game Pass.
When games are installed from the Microsoft Store, they are installed into special sandboxed folders, isolated from the rest of your files and programs. Notably, by default these sandboxed folders are not even accessible to your user account, only to the special system TrustedInstaller account.
This means you cannot (by default) read, modify, change or replace any of the files in a Microsoft Store-installed game's directory.
AppData WorkaroundFortunately, UE4 games load their mods from multiple places, and only one of them is in the install folder. The other is in a special folder in your user data folder.
The
AppDatafolder is full of extremely important, often sensitive, and frequently hard-to-recover files. Exercise caution mucking around in there manually.
We can abuse that method to load game mods without having access to the game folder, but this won't support everything.
Reportedly, this method does not work for some users at all, and causes the game to crash upon launching. In that case, your best solution for modding Project Wingman is, once again, to purchase a copy on a platform like Steam or GOG.
Vortex should be able to install and deploy mods for the Microsoft Store version of Project Wingman, but this is unsupported. That means I'll try my best to keep it working but I provide no guarantees, and I generally can't help you with debugging problems with the Microsoft Store version.
Just as with the Steam/GOG versions you can always install and manage your mods manually, but the process is a little different for Microsoft Store games, since you can't use the usual guides and instructions.
Essentially, you should be able to drop your .pak files into the %APPDATA%/Local/ProjectWingman/Saved/Paks folder and the game should load them the same as if they were in the install directory.
In short, there are no plans for Project Sicario Merger (PSM) to support the Game Pass/Microsoft Store version of Project Wingman. That means mods that require PSM will not work with the Microsoft Store version and you will not be able to merge your installed mods with that version of the game.
As covered at the start of the guide, if you really want to mod Project Wingman to the fullest, buy the game from Steam or GOG.