From what you've posted, you're running Sonoma on your MacBook Air, and your default search engine, which used to be Google, is no longer available.
Can you provide more details on what you see when you go to Safari-->Settings-->Search? Is there nothing available in the drop down menu there?
Regarding apps, the only one we recommend folks use is Malwarebytes. It's available Here. You should only need to download/install the free version to check for malware on your Mac.
Other anti-virus, "cleaner", or "optimizer" apps you may run across simply cause more issues than they prevent, so do not install any of them, as you'll soon be back here asking for additional help.