Although I hate the Brave browser, the search engine is the most useful of the others. It gives me the most correct results compared to the others, even it sometimes ignores the quality resources.
I wonder your opinion about the search engine. Do you have any negative ones?
Whoogle also use the Google search API, like Startpage. But Whoogle is FOSS, you can selfhost it, or use one of it’s open instances. But this you must see by yoursel which works best for you.
For other search engines, you can look in the Vivaldi Forum, there is maybe the most complete list of search engines you can find, complete with insert code, made by an user
https://forum.vivaldi.net/topic/46609/guide-vivaldi-search-engines-collection