How to search AWS documentation?

I have been studying towards my Cloud Certification Exam and as such have been doing a number of practice questions as a way of developing my understanding of AWS.

When I come to a question I don't understand I go to the AWS documentation page https://docs.aws.amazon.com/ and use the search bar. However I find that this approach rarely if ever returns a helpful result.

I had considered the obvious angle: that my search terms were poorly formed, so I tried something else. When given documentation on a very specific topic, I tried to find my way to that page from https://docs.aws.amazon.com/ using key phrases, such as the title of the page and seemingly unique phrases within the page. This second approach also failed me. I'll give an example.

Lesson 4 of 11: Amazon S3 Fundamentals has a link to the page 'Organising objects using prefixes' https://docs.aws.amazon.com/AmazonS3/latest/userguide/using-prefixes.html

I've read the page and it makes sense to me, but I know that in future I might like to find it again if I forget some crucial details. So I test that I can find it by going to https://docs.aws.amazon.com/ and using the title of the page (Organising objects using prefixes) as the search term.

The correct result (that is to say, the one I am searching for) does not appear in the first ten pages of results. So I use the 'User guide' filter on the left hand side of the page and this puts the correct result at the top. The problem with this should be obvious however, there are many filters and it takes a process of trial and error to find the appropriate one.

Going the long route and searching via an external search engine like duckduckgo puts the correct result as it's first listing too, so why doesn't AWS documentation search perform so poorly at this task?

I have given just one example. But I could provide as many as you have time to examine. The frustrating thing is that when I'm researching something a little more obscure I have no confidence in the AWS documentation search function to ever use it.