[wslh]

Use [Search Tools] => [All Results] => [Verbatim] that is a known issue for people who have been using Google Search for years. There are many discussions about this topic, like: https://www.webmasterworld.com/google/4744658.htm

[kuschku]

Even that doesn’t solve all issues – it still shows results that are irrelevant to my query and do not even match the query.

It should not be hard to convert a query into a regex for content, title and URL and apply it on the index.