How do I stop Google becoming default, when I set Safari as default browser?

Explain what you're experiencing. What do you mean by "it goes to google"?

Google isn't a browser, but Google Chrome is. Do you have Google Chrome installed on your iPhone 15 Pro Max? Or is Safari merely configured to open a Google search page?

For others, it was because they used Gmail and there is a setting in that app that you can have the service use Google instead of the Default Browser that you have set on your device.

Do you have a different Google service that would be overriding your wishes in using your Default Browser?