I personally use Google Chrome with the duckduckgo search engine. Duckduckgo is not perfect, very in depth searches (such as gameboy advance memory layout only return junk, while google knows you are searching for a nich) but on your average search it is as good as google, somethimes better because it is more factual and will promote less webstores. When it does not give me what im looking for I can add !g anywhere in the question and the same search is done using google.

Then I use Violentmonkey an open source js/css injector to inject this user script: https://greasyfork.org/nl/scripts/1682-google-hit-hider-by-d... This will block specific domains for you in google, yahoo, duckduckgo etc. I use this to block domains like Quora, sourceforge, cnet and softonic.

The nice thing about this script is that you can permaban domain you know are junk and they will completely be removed or you can ban a domain like commercial websites. When you ban something it is not removed from google or duckduckgo but it only shows the title in light gray, Im currently experimenting with this on some mayor webstores so I can not really say if this may help you but It can be a good start.

(edit) I saw some people say why this was not possible before. Google allowed you to block domains and website a few years ago, but they removed this feature. Duckduckgo never allowed you to do that because that would mean that you will have a cookie that remembers your preferences and that is against there principles.