it always work if you login into a Google account prior to downloading. If you don't, indeed the downloads will regularly fail.
"Chinese repos" refer to the fact that the debian repos links for updates point to custom Huawei servers.
That was not my experience, at least for very large files (100+ GB). There was a workaround (that has since been patched) where you could link files into your own Google drive and circumvent the bandwidth restriction that way. The current workaround is to link the files into a directory and then download the directory containing the link as an archive, which does not count against the bandwidth limit.
I am somewhat amazed how you can manufacture such expensive high tech equipment yet are too cheap to setup a proper download service for the software, which would be very simple and cheap compared to making the hardware itself.
Maybe it is a Chinese mentality thing where the first question is always "What is the absolutely cheapest way to do this?" and all other concerns are secondary at best.
..which does not inspire confidence in the hardware either.
Maybe Chinese customers are different, see this, and think "These people are smart! Why pay more if you don't have to!".
My company hosts our docker images on quay.io and docker hub, but we also have a tarball of images that we post to our Github releases. Recently our release tooling had a glitch and didn't upload the tarballs, and we very quickly got Github issues opened about it from a user who isn't able to access either docker registry and has to download the tarball from Github instead.
It doesn't surprise me that a lot of these companies have the same "release process" as Wii U homebrew utilities, since I can imagine there's not a lot of options unless you're pretty big and well-experienced (and fluent in English).