Websites don't just use #JavaScript fingerprinting and #cookies for #tracking, but also certain URL parameters.

For example, when you click on some call-to-action button, you may be sent to https://example.org/destination?utm_content=call-to-action-button instead of just https://example.org/destination

Fortunately, #Firefox 102 will be able to remove those parameters. Until then, it is recommend to use the #ClearURLs addon: https://addons.mozilla.org/firefox/addon/clearurls