Unable to locate files using Finder

Have you reindexed the drive for Spotlight? How to rebuild the Spotlight index on your Mac - Apple Support

Also download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Add Text button to include the report in your reply. How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report

Before running Etrecheck assign Full Disk Access to Etrecheck so that it can get additional information from the Console and log files for the report:

Then we can examine the report and see if we can determine what's causing the problem..

I'll expand on what Old Toad wrote.

Try a safe boot.

Shutdown your machine.  Hold down the shift key.  Poweron.  The boot up will take longer than normal because the filesystem on the startup drive is being checked and repaired as needed.   All about safe mode including what features and apps safe boot leaves out.  Safe boot uses a software driver instead of using your machines video hardware.

Use safe mode to isolate issues with your Mac - Apple Support

For finding files, I like to use "Find Any File" app.

https://apps.tempel.org/FindAnyFile/index.php

R

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