About .6% of the world is considered as living in modern slavery.

In say, the feudal era, that percentage would be some 70 or 80 times higher.

Maybe you should do some reading?

Modern slavery includes forced labor, bonded labor, trafficked people, and child labor - it’s analogous to chattel style historic slavery in that the conditions are similar.

No, no it's not. NGOs conflate them sometimes to draw attention to an important issue, but it's a large continuum. A job where you can't quit early is not the same as what's in Roots.

Actual chattel slavery still is around in places, but only pretty marginal and lightly populated ones. Mauritania is an infamous example.

Current estimates are 50m people living in these conditions today, vastly more than at any time in human history.

Global population in 1 AD was around 200 million. 25% slaves isn't impossible. It kept going up from there and slavery wasn't seriously challenged as a concept until the 1700s.

And going by absolute number instead of proportion is another lie with statistics you might be repeating. Yes, population has grown. What does that have to do with it?