First of all check if fulltext search is not activated. If you go to the Fulltext Search Options submenu you can check if it's indeed deactivated: https://i.imgur.com/9Mzc5tG.png
Even if so, save the settings, just in case. In fulltext mode the adjustable relevance is ignored, because fulltext search database uses internal relevance values.
After that, you should adjust the Relevance Values. You can read more about them in the documentation: http://wp-dreams.com/demo/wp-ajax-search-pro3/docs/#search_relevance_options
Basically you want to decrease the terms weight, increase the title weight, and decrease the content weight.
Try values like:
Title weight: 10
Content weight: 5
Terms weight: 2 (or 1)
These should increase title relevancy, and decrease content and terms relevancy by a bigger factor.Best,
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