So this has happened to me now on two brand new Quest 2s.
I turned on my Q2, went through set up, connected to my wifi network which showed up fine & the Q2 went through an update. I was then able to get into the main useage & all worked fine for a while until a reboot & then the Quest 2 could not see my wifi networks.
I googled, I tried connecting via the app but it kept saying incorrrect wifi credentials (they weren't), I changed setting to 5GH channel, all to no avail. So I returned thinking I had a fawlty one.
Bought a 2nd one today & exactly the same happened, it saw my wifi networks, connected, updated & then after reboot cannot see any wifi networks & thus won't go past the setup screen. On this one I didn't get any usage. Very very frustrating.
Lastly I'll add, I use 2 mobile phones in hotspot mode for my internet, this works fine with absolutly all of my tv boxes, laptops, tablets, alexas etc & the Q2 saw & connected first time round so this has to be an issue with the update?