> a different type of slavery, just as historically there were lots of variations of slavery, with differing levels of what a slave could do

It’s not and it’s absolutely ahistoric to make this claim. (Not disputing that it’s a popular view in some circles.)

> Work for a wage (AKA sell their time and/or bodies), or die

They can change employers. Slaves can’t do that in any system. If you want a proper comparison it’s to serfdom.