Removing Cache from Safari running Mojave

Safari 12 macOS Mojave

Caches folder is stored in container and SIP protected.

A user can "Empty Caches" from Develop menu.

  Safari > Preference > Advanced

      Checkmark the box beside "Show Develop menu in menu bar".

      Develop menu will appear in the Safari menu bar.

      Click “Develop”  to show the dropdown.

      Click "Empty Caches" from the dropdown and test.

Click "Empty Caches" again.

      https://support.apple.com/guide/safari/use-the-safari-develop-menu-sfri20948/mac

Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J.  When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder.  Select Library/Caches/com.apple.Safari/Cache.db and move it to the trash.