Good day! I'm Raniel, an Independent Advisor and a Microsoft user like you.
Kindly try open file explorer, go to the folder where you need to search the file with the content and enter the search term~="xyz" instead of content:"xyz".
If that didn't work, you may use a tool called Agent Ransack(free version) to search for the file: https://www.mythicsoft.com/agentransack/
I hope this helps. Good luck!
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