Thank you for the details, I have checked your configuration, and found a few issues, that I fixed.
1. Some taxonomy terms were also choosen to be returned as results, which I believe you don't need, as you only want the knowledge post type as results, nothing else. I have removed these taxonomy terms from the result sources: https://i.imgur.com/iZj4CFh.png
(if you intended to display these as results, then my apologies)
2. Based on your descritpion I assumed you want closer matches to exact phrases, so I changed the search logic configuration as following: https://i.imgur.com/G53pdT7.png
This configuration prefers exact matching, if no exact matches (or not enough) are found, then a secondary fuzzy matching with the 'AND' logic is executed as well. It will very likely return much more relevant results.
I hope this helps!Best,
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