Well, I went through all of that and when attempting to redownload the desktop app via your Step 3 link the page for the download times out. Tried on three browsers, no VPNs or firewalls to muck up the connection. Any ideas?
Edited to update: a manual launch of World of Warcraft has initiated an installation of the Bnet app on it’s own, so I’ll update at a later point if the original session error persists.