I’ve had something similar happen with a few different iOS updates.

Usually I’ll just reset the network settings (Settings > General > Reset > Reset Network Settings) and that seems to resolve the issue.

Obviously the ideal solution would be for Apple to fix this, since resetting network settings forgets wifi passwords.

But as far as I’m aware the issue doesn’t affect everyone, so could potentially just be some minor corruption occurring during the network/modem firmware upgrade.

Forgetting passwords shouldn’t be a problem these days, we got iCloud sync

My phone updated twice but the version number is the same 14.6, they are about 2 days apart.