Error 0x800704c6 trying to update/reinstall Gears Tactics (Win10, Xbox Game Pass)

[There doesn’t seem to be a definitive place for game installation/troubleshooting questions. This may possibly belong on gaming.SE]

I’ve been playing Gears Tactics on Windows 10 via Xbox Game Pass for the last few days. Everything was working fine until it tried to install an update yesterday. The download hung at 246MB out of 2.8GB, with an error code 0x800704c6, message “couldn’t connect to the service”. I cancelled it, which uninstalled the entire game. When I tried to reinstall, it hung again, at the same place (but now out of a 28GB download).

Things I’ve tried:

• Reboot the machine
• Repair/reset/uninstall/reinstall the Xbox Beta app
• Run the Windows Store troubleshooter
• Reboot with a clean start (no services/startup apps loaded)
• Install from the Windows Store
• Install from the Xbox Beta app

Is there anything else I can do, short of nuking and reinstalling the OS entirely?