1. Well, there is not much to do in this case unfortunately. The plugin tries to check phrases with different beginnings and endings, but it stops there, to avoid performance problems. With more complex queries it would slow down extremely or never return results in worst case.
2. I've looked at your installation, and I made a few changes in the plugin configuration which I believe is closer for your needs.
– You had the Show exact matches only option activated – this already prevents mixed phrases as there is no item exactly matching “Płyta Egger Aluminium” in any of the fields
– Then I changed the keyword logic to AND as you have many products, this will fit much better: https://i.imgur.com/faQNdlM.png
– ..and since you need the logic to apply on mixed phrases from different fields you need the index table engine, so I configured, created and enabled it for you.
Now if you search for example “Płyta Egger Aluminium” it will show the item which has all of these words in any of the selected fields (title, content, excerpt and category names)
3. It's possible, but only with a custom code. You can use this one, in the functions.php file in your active theme directory:
Basically change the $mapping array to the items you need. To the left side is the word you want to replace, to the right goes the replacement. I hope this helps!Best,
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