Query posts by categories and tags using free text search

I’m currently building my own search results page which takes a value from the URL. I’m able to query the post title easily enough by using the S parameter however I’m wondering how I could expend this to also query categories, tags and the maybe the excerpt?

Obviously, as the value is from a text input it’s going to have to be some kind of “LIKE” query.

If someone could point me in the right direction I really appreciated it.