Seems strange that they wouldn’t just use the XBox authentication app system and keep the file delivery via Steam at least to the extent the core data and install media is possible before any other assets.
Wonder if it’s down to server side load and delivery issues or at worst the UWP back end and content delivery which basically amounts to delete and re-attempt and hope the [beep] data doesn’t break in some way.
(Newer games having this delivery data in addition to the game data that can also corrupt.)
Hopefully they also fixed issues with using separate non-OS drivers for downloads and other issues but the apps lack a lot of options even through stuff like policies or registry editing and the folder system is part encryption part sandbox environment even if the structure can now be Win32 based too.
Logging perhaps if that’s even done at all otherwise one just has to terminate the process and attempt it in a hour or so maybe flush the DNS or whatever to clear connections so it doesn’t do any background stuff it’s kinda difficult to work with the Windows Store structure although thankfully I’ve only had one problem where a patch was more like downloading the entire thing all over but otherwise avoided file corruption and download problems though these are still a thing and I have no idea on where some of these problems even begin even after multiple OS updates and app updates.
(Back end then and server side issues potentially.)
EDIT: Even if the game is a bit like a MMO with content updates and the delivery system at least a majority of the core data could have been part of the Steam download alleviating additional download issues and possible server queues and connectivity problems as I see it.
(Well not really a MMO but a lot of content that can change and be updated significantly plus the dynamic content downloading and streaming although I suppose that’s more like additional downloads on top of this initial data.)
Bah it could have been handled better simply put, Gears of War 5 and some other recent Win10 Store titles (Halo Collection I guess?) did after all.