For things I access often, the Firefox address bar does function like a near-perfect search for me. Some things I type [ab cd] and the page with the words _starting_ ab and cd pops right up.

A while back I looked up a manual for an old Singer sewing machine, which turned out to be the model 15. So I typed [sin 15] in the address bar and -- yep, first result! A week ago I looked into the game Metroid Dread. Typed [met dre] and two relevant pages from my history came up, immediately.

I don't know what you mean by "100% unique match" but, this feature works for me, and in fact I regularly use it and find it very worthwhile.