iOS15 replaced WiFi protocol WPA2 with more secure WPA3. I'm sure you'll "appreciate" that you can now use "easier to remember passwords". Actually NOT - as I can't connect to it anymore. I've been working in IT security for quite some time - good security is useless if it breaks 90% of connectivity. I can't use iPhone hotspot with my car any more, neither with not-so-old laptops. Pretty crap if you can't downgrade it in the hotspot configuration!

The problem is the new "more secure" protocol - WPA3. It's damn secure as I even my devices can't connect to it. I wonder if Apple gets paid by mobile network providers for saving them data bandwidth.