The range extends the range from 1 to 4.

With '1' you only block cookies from sites that are on a block list. This is a new setting that is when Firefox got basic Tracking Protection. Enhanced Tracking Protection added more blocking features like Cryptominers and Fingerprinters.

The other settings (2-4) are the legacy cookie settings you may know from the past (before TP) and do not use a block list like '1' does and you extend with 2 to 4 what is blocked . With '2' you only block cookies from sites that you haven't visited before (no history present) and you allow cookies from sites you have visited. With '3' you block all third party cookies unless you have a cookie allow exception. With '4' you block all cookies, first party (current domain) and all third party cookies unless you have a cookie allow exception.

If '3' blocks all third-party cookies, and '4' blocks all cookies, then wouldn't they also block all the cross-site and social media trackers on the block list too?