neowin[.]net/news/complaint-filed-against-mozilla-firefox-for-ppa-default-tracking-as-most-users-are-dumb/
Since v. 128 Firefox uses Privacy Preserving Attribution (PPA), which similar to Google Chrome's Privacy Sandbox, is supposed to take the place of tracking by/with cookies. By default it's turned on -- you can opt out:
In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version. Click the menu button and select Settings.In the Privacy & Security panel, find the Website Advertising Preferences section.
Uncheck the box labeled Allow websites to perform privacy-preserving ad measurement.