Support was kind enough to send me a refurbished/warranty controller… which also did not work.
In the end, I had to do a hard reset on my Asus router and reconfigure my networks to get it working. The new controller came online within 30 seconds of my freshly reset router rebooting. I have no idea what caused the issue as I wasn’t home at the time it went offline and according to my router logs there were no changes made for at least 30 days prior (it was more like 180 days since I had replaced the router)