PsfTooling
PsfTooling is our simple free tool for injecting the PSF and solving other shortcut related issues when repackaging using the Microsoft MSIX Packaging Tool.
This is how we fixed up MSIX packages "in the old days", before we had premium software like TMEditX Editor. Ultimately, this tool is limited in what it can fix because it is used while you are in monitoring mode of the Microsoft MSIX Packaging Tool and your package depends on that tool to create the final package. So while it does add the PSF when needed, and solve so additional launch-related issues, it can't manipulate the AppXManifest file, meaning that it cannot add extensions to the AppXManifest that Microsoft has added but not updated their own tool to use.
We estimate that you can get about 70% of applications to work with this technique, but not the 95+% we measure with TMEditX.
But hey, it is a free community tool that might still be useful to you if there isn't budget for TMEditX Editor (which isn't really very expensive by the way).