why does my safari search in google switch to bing?

Hello!

This may be due to one or more extensions or programs that you have installed on your Mac. I would recommend you first verify within the Safari preferences/setting that you have the search set that you want. Once you do that, check and see which extensions you have installed and try turning those off or removing them.

Let me know if this helps or not!

You have adware/malware installed. Use  Malwarebytes Anti-Malware for Mac. It may be necessary to run more than one scan. After scanning a couple of times, restart the computer and test. If necessary, follow the manual instructions.  Do not download any other programs that are listed in the articles.   Malwarebytes uninstall

 https://www.2-spyware.com/remove-bing-redirect-virus.html

 How to get rid of Bing.com Redirect - Virus removal guide