Does "wage slavery" just mean "most people are required to work in order to survive" ? If so, every society in history is like that.

No, it means people are forced to work multiple jobs because no basic social mechanisms, and when you are poor you can be jailed (and then exploited as a slave, slavery still pays billions per year in US) for nothing (https://twitter.com/dylanogline/status/1550121929939398656 for just one example). Not to mention many mechanisms, like student debts, seem designed to force people into military (https://twitter.com/repjimbanks/status/1562820837140742144).

(Not OP, idk how she defines it). Freedom is a spectrum. There are some parts of American work life which limits people's freedom. The non-livable wages for much low income manual labour means many needs to work multiple jobs, and makes it hard to save money, so you live hand to mouth (less freedom). Tying healthcare for you and your family directly to your current job is a major freedom-remover, even if you save up money to survive a month between jobs it can literally bankrupt you if you or you family gets sick then. There are of course places which are worse, but there are also places in the world where people can quit their shitty jobs knowing that their kids will still get healthcare and school no matter what.