After iOS update, Safari shows this (search engine is Google)

That message will appear if you are using a "captive network", among other possible reasons.

Use captive Wi-Fi networks on your iPhone or iPad - Apple Support

Might that be a factor? If not, try temporarily turning off Wi-Fi on your iPhone, and connect using your cellular data plan (assuming you have one, and that it works in your area).

The particular website (Google in your case) is not important. For example try typing https://www.apple.com in the Safari search field, and see if a similar message appears.

Still need help? Reset that iPhone's network settings according to the instructions here:

Reset iPhone settings to their defaults - Apple Support

Don't reset all anything else. Just network settings.

Try and go to google.com and put your search query there to see if the issue persists

if it persists it seems like that google has some issues with their certificates