I was trying to create an offline deployment of Microsoft Photos and kept getting stuck on install with error 0x800700B7. All forum posts I could find were about this error from the MS store itself with very generic troubleshooting steps. The most helpful of them is to do a Windows Store reset with the command "wsreset.exe". This was not my issue though.
You can copy the MSIX file and its dependencies locally to run and get a clearer error. In my case I had accidentally picked an older version of the app. The error was telling me that I have a newer version installed.