The search bar doesn’t work perfectly

I’m creating a blog for my company. The filter works perfectly well (pro version). I’m happy with it.
The only problem is the search bar:

how can I configure it so that what it displays works correctly?
– Can I use the experimental css block? And if so, how can I focus only on changes to the search bar?
– Or can I use a plug-in compatible with your revelanssi plug-in?

I’d like to be able to search for words in the articles or title: only posts, function and not gold if several words in the search, most relevant posts at the top…

thank you in advance

The page I need help with: [log in to see the link]