Since you can never be fully certain whether or not a search provider is abiding by its privacy policy, I generally try to spread my searches out around as many search engines as possible to make it harder for any one of them to piece together a complete picture. DuckDuckGo, Qwant, Brave Search, Swisscows, MetaGer, a few Searx and Whoogle instances, and Startpage all make the list.