Apple will not release an update to fix your iPhone, because there is nothing broken with the release. If there were you would see thousands of posts about it from the several hundred million users who have updated. There IS an issue with your iPhone, but it is your phone, not the version.
Have you tried any troubleshooting, such as restarting your iPhone? Restarting your router?
Do you have a 3rd party VPN installed, even if you are not using it? If so, delete the VPN profile in Settings/General/VPN & Device Management/VPN, then restart your device. Don't just turn it off; delete the profile. Updates sometimes "break" VPN, and it needs to be removed. If that fixes it, you can try reinstalling VPN, but probably shouldn't.