I logged in to the Azure portal and then went to register an app. Under supported account types I selected "personal Microsoft accounts only". When I try to enter the url for the SPA I can't enter obsidian://msgraph. Says it must start with https or http://localhost. I had to select the Azure and personal accounts option. Haven't installed and configured yet, but thought you might want to update the docs to reflect this. I'm assuming this will work.
Also, can you set up to work worh BRAT?