How can I change my search engine in Safari without 3rd party extensions?

I have been wanting to use the Ecosia search engine to help plant trees in Africa. They used to have an extension where you could search in the address bar and it would use Ecosia. However, apple is removing extensions and is relying on installing App Store apps. Ecosia does have an App Store app but you have to manually click their button and search through instead of searching in the address bar. You only have options to change your search engine to Google, Yahoo, Bing, and DuckDuckGo. I would like to have a feature to add other search engines. I may switch to a different browser for now until safari will be able to do this.

I am wondering if there's a way I can already do this by accessing different files in the Root File System. Probably won't work haha but just putting this out there.

Thanks!