[2020] Installation Stays at 0% (Gamepass)

Installation is done by the MS store app rather than the game itself, of course. Have you tried using the beta Xbox app instead?  

Hmmm. I haven't seen other such reports. Can you install any other game or app with those utilities?  

I don't know then. Can you try on another machine? Or another Windows user on this machine?  

You can create a second Windows user on this same machine, log in as that and try the install that way. If that still fails I think your Windows store/gamepass setup in Windows is broken, I'm sorry. You'd need Windows support help with that.