quickest way to make google my search engine?

If it's not Chrome: Firefox has it under Settings, Search, Default Search Engine. Edge buries it at the bottom of Privacy, search and services, under Address bar and search. On an iPhone it's in the phone's Settings app under Safari, not inside the browser.

In Chrome it's Settings, then Search engine, and pick it from the dropdown. Ten seconds, assuming nothing else is quietly resetting it on you.