Perhaps if we consider slavery as more of a spectrum, like we do other kinds of abuse, then economic coercion still fits the definition.

One person being denied medical care, working inhumane lengths of time in hard labor for almost no money, being unable to access different forms of work and being beaten is clearly slavery, as you've identified. But that doesn't mean the person who is experiencing all of that, but only without being beaten, is not experiencing slavery. It just makes it a (possibly) less severe form of slavery.

If the key difference between a fast food worker living in rural wherever who can't access healthcare, doesn't have a choice to move or change jobs etc. and a slave is immediate physical violence... perhaps we need to revisit the definition of "slavery" or of "employment" or both. Dying a slow death from homelessness and poverty due to systemic inequity isn't actually a hugely better deal than a fast death at the hands of one person. In some cases it may even be worse because the suffering lasts much longer.

You assume that people who are unemployed can access help and resources, I'm not sure that the reality on that widely reflects people's experiences, depending on their location.