“What does legal freedom actually amount to...?” — 

The sentence:

“What does legal freedom actually amount to when the parties possess radically unequal resources?”

can sound as though you are questioning whether legal freedom had any real significance.

That is not your argument.

Your argument is:

Legal freedom was real and transformative, but unequal resources constrained the extent to which some of its implications could be realized.

So your better sentence is:

Legal freedom was established through emancipation, but unequal resources constrained the extent to which formerly enslaved people could exercise some dimensions of that freedom in practice.

That preserves both sides:

real legal transformation + limited practical realization.