Phasma Felis

Most of the interesting mods for Outer Worlds involve editing game files. After hours of trying, and multiple tutorials that don't work, I haven't managed to convince Windows to let me edit anything in C:\Program Files\WindowsApps, where the Windows Store installs things. Has anyone managed to mod the Windows Store version at all, or is it completely impossible? If that's actually the case, I'm cancelling my Game Pass and buying it from Epic. I don't like them much, but as far as I can tell they don't try to lock me out of software that I paid for.