With respect to employment rates I don't think you can use the US as an example. US states are not countries. The barrier of movement for money, people and companies is basically zero.

The problem with the US is that you get a race to the bottom on everything. Consider two states A and B. A has high taxes and great school system, while B has minimal taxes and bad schools.

Companies get founded in A thanks to well educated public. But because the transaction costs and movement costs are so low. They find it beneficial to move the company create in A to B. Meanwhile the highly educated top earners in A also move to B to get those jobs.

At the same time the poor and disabled cared for very little in B move to A, causing an overburden on their social system.

Do you see how this isn't workable with free movement of people, companies and money? It makes any progressive policy fail, but that doesn't mean those policies are bad. You basically just set them up for failure. You get a race to the bottom.

That is why the US has so much homelessness and poverty problems. Nobody wants to be the sucker to deal with those problems. You have a tragedy of the commons situation, or what I would call the prisoners dilemma. It is why you research paper linked is in my opinion pointless. The outcomes could easily be predicted from game theory. But they fail to put this in context.

A much more realistic outcome is seen by comparing actual countries. Here it is clear from the Nordic experience that strong employee protections does not in any way impede employment.

The devil is of course in the details. It is not like you can make any arbitrary law and it doesn't have consequences. The point is that it is possible to come up with a system with the right mix which does not have problems with employment.