Sorry, I forgot about that. You can change the minimum characters to enter to trigger from 0 to 1 or more here: https://i.imgur.com/OmEeIJ6.png
You should still try to fiddle a bit with the logic and the relevance values. I see a lot of lengthy content with many many words, so I would rather suggest trying the “AND with exact keyword matches” logic – there is a very high chance with that many words for matches. Additionally setting the secondary keyword logic to “AND” is a good practice just in case.
As for the relevance values if the titles are important, then in your case it might be beneficial to increase the title relevance by a lot. See with that many potential matches within the content it is possible that items with lot of partial occurences may get a higher relevance (just because of the high number of occurences). To balace that, you can increase the title relevance to something large like 300, and simultaniously reduce the content and excerpt relevances to 1: https://i.imgur.com/cuoky2R.png
That should make a significant change in the results order.
