Uploads going to the root of wp-content/uploads

What else to check?

First, deactivate all plugins and switch to a different theme. Then test uploads.
If its fixed reactivate plugins/theme one at a time until you find the culprit.

Next, you can check the database options table to see if the upload_path or upload_url_path have been altered, they should be blank.

Then, you would have to start checking the WP core files. Try reinstalling. If that doesn’t work.

Nuke the whole thing and walk away… Or just leave it, if its still functions fine.