If you use the Files app, and go through everything you can find there, can you find the large files or large number of files anywhere there?
In the Files app, click the hamburger menu (icon with three horizontal lines), then on your phone name. You should now see a list of folders like "Alarms", "Android", "DCIM", "Documents", "Download" and so on. Go through everything and see if you can find the large files or large number of files. Pay special attention to everything inside the "Android" folder.
If you find them, can you take note exactly in which folder the files were? That might reveal what app created them.
Files created here in your home folder most often doesn't count as either storage or cache for apps, so doesn't get cleared when clearing cache, and doesn't count as app data, just "Other".