is there a sensible way to change default search engine in chrome?

Check it's actually the search engine that's wrong, too. The startup page and the new tab page are separate settings, and an extension can take over the new tab page while the address bar still searches Google - it looks like the same problem and isn't. If you've tried everything, Settings > Reset settings > Restore settings to their original defaults clears the lot without touching bookmarks or passwords.

It is under Settings, then Search engine, then the address bar dropdown. The part worth knowing is why it sometimes refuses to stick: an extension with permission to change search settings will quietly put its own back every time you restart, and Chrome will usually say the setting is controlled by an extension if you look at it properly. Disable them one at a time until it holds. If instead it says managed by your organisation, that is a policy pushed to the machine and you cannot override it from the settings page - that one goes to whoever runs your IT.