How can you find and replace text in wordpress files on localhost xampp folders?

I don’t believe you can as a general rule just use a simplistic text search to find content even in Drupal.

Any non-trivial data organization will probably use serialization, json encoding or totally separating the location of different parts of a data at different places of the DB or code and combining them when a page is generated.

A leading element in “what you see is not what you have written” are shortcodes, which generate html which seems to be part of the content, but it is not as it is generated from meta data or external resources.

The more complex the site is the bigger the chance is that you will run into content that is composed that way.