Here are the issues I've faced with some of the alternatives: 1. Duck: Used it for years but the quality of results has taken a nosedive lately. 2. Startpage: Was good when it used to get results from Google but now it's a mix of Google and Bing. 3. Metasearch engines (SearX): Unreliable since they rely on scraping. 4. Kagi: Results are not better enough to consider paying for it.
That being said, I don't have my Google account logged in while doing searches.