There is a German article, that goes in depth on how to disable pretty much all of them and explains what they do: https://www.kuketz-blog.de/mozilla-firefox-datensendeverhalt...

A few of them actually do make sense for a normal user (i.e. the Wifi portal stuff). But you can disable it if you spend some effort on it or you can also use an alternative build of Firefox without it. Not great, but also not terrible imo. Sorry, that I have no English source.