I too, thought I was crazy until I see this thread.
Both my family and I got the iPhone 13 Pro, where I set mine up 2 days ago and had been working fine.
My family just set up today and was experiencing this WiFi issue.
Went to Apple Store and tried the WiFi there. Mine worked immediately and the family's one exhibited the same issue.
Ask those Geniuses at the store about this, and they told us to make an appointment to have the diagnostics done, when they could have take a quick look at this VPN-related bug and send us on our merry way.
Made the appointment and found this thread as soon as I got home.
Turns out the family one got Surf Shark installed. WiFi came right back on as soon as I removed the app.
Can't say thank you enough to you guys!!