For when you were slaves of sin, you were free in regard to righteousness.
Romans 6:20 ESV

By “free in regard to righteousness”, Paul clearly means that the slave of sin is free from any considerations of obedience to God’s Law. If you are condemned already, what is the point of attempting to obey? It can’t gain you anything in God’s eyes. It can’t reverse your condemnation. It can only burden you with pointless obligations. See John 8:34.

> A slave to sin = under law = lawless = free from righteousness = death
> A slave to righteousness = under grace = obedient = free from sin = life