Hello Robert,
If the web browser is hijacked, then no antivirus or antimalware will fix these settings for you. You could attempt using another browser to see if you are getting the same results or if the issue is specific to Google Chrome.
Malwarebytes and Zemana should be sufficient enough for scanning your phone for Virus’ and Malware.
Please let us know what your default search engine is in google chrome, and try using another browser.