Thanks for sharing. Sorry you had to go through this, I haven’t heard of any issues with ASUS routers, that is usually our power house (I have one at home and we used to run everything on one at work ASUS RT-N66U).
For anyone reading this, these are not normal steps, but using a hotspot is a creative solution.
This is only for Gen 1
For only pairing this might help…
Were you using a Gen 1 or Gen 2 device? Gen 1 is blinkup, Gen 2 is the Apple WAC process.