I want a search engine that only returns results containing words I specify. Is that asking too much? Google is not that search engine.
Maybe try Kagi. I am pretty happy with the results.
I felt the same frustration: I just want keyword matching without any filtering. I'm building https://greppr.org/ to scratch that itch.
remember when "Human speech" -robots -alien worked? those were the days. I guess there's just too much data now to search stuff like that.
I think google several years ago had gotten very good at matching on related concepts, but it just fell off a cliff after that.