I recently put in a fresh Windows 10 installation on my PC and I cannot download the battlenet / World of warcraft installer. The download always cuts to the last .1% and it gives an error message of Failed-Network error. I can download and install Steam / Uplay and the Epic games store just fine.
Is the drive you are trying to download / install to running out of disk space? I doubt this is the issue but it’s also possible you are running out of ram on the download depending on how big they are (easiest way to track that is just start the download and open task manager and watch to see if your memory % starts to get really high). The last thing I can think of is if they are being interrupted. I know I was getting some weird lag in game in the past week or two, maybe that can extend to packet loss for their downloaders