I have been tinkering with Powershell off and on as time and circumstances permit.
You may be able to create your own "search engine" without too much effort. Especially if you can find and adapt some existing script to your need.
Four basic steps:
1) Search for a specific word occurrence in a single text file in some folder.
2) Count the word finds
3) Expand the search go through all of the text files in the folder.
4) Tally the word count if and as necessary.
Google words such as "use powershell to search text files tally word count". You can vary the words and phrasing to refine the search results.
Example links:
https
/stackoverflow.com/questions/42271475/reading-a-text-file-and-finding-text-using-powershell...