> You can probably draw a linear relationship between the amount of employee protection in the laws of a country and its unemployment rate, especially among younger people.
You can not draw a linear relationship between those. Top unemployment rates over the last 10 years: Greece, Turkey, Spain, Costa Rica, Poland, Slovak Republic... [0]
One thing you're ignoring is that countries with strong employee protection also tend have a strong social safety net where unemployed people have a backstop, they haven't lost their healthcare and assistance, so being unemployed isn't the peril it is somewhere that employee protections are basically nil.
Correlation is not causality, strong tenant protections allow people to live in places longer term, which is seen as desirable to forming neighborhoods and bonds among neighbors, which in turn makes it a more desirable place to live. Homelessness in a specific place has a diverse number of factors that play into it, including geographic factors, from ambient air temperature, housing prices, employment availability, social services available, etc etc etc. You can't draw a line from rent control to homelessness unless those are the only two graphs you're looking at.
[0] https://data.oecd.org/unemp/unemployment-rate.htm#indicator-...