I just recently made the choice to discern between “sin” and “dead works”, dead works being a subset of sin:
Sin: Disobeying God’s law.
Dead works: Doing good things to improve your chances of salvation.
In fact, Hebrews 12:1 nails it: “Therefore, since we are surrounded by such a great cloud of witnesses, let us throw off every encumbrance and the sin that so easily entangles...”
IMO, the “sin that so easily entangles” is the belief that we must “be good” to receive salvation, coupled with working towards salvation, rather than simply accepting it and then going forward knowing we are His heir.
Dead works are based on the fact that for EVERY.OTHER.RELIGION. you need to save yourself - from Sanatana Dharma: Hinduism/Buddhism/Jainism you have to escape the cycle and build your own karma. Similarly Zoroastrianism is about being good, Judaism / Islam is about following the rules.
Christianity is a revolution in that case --
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yet we have Wherefore, my dearly beloved, (as you have always obeyed, not as in my presence only, but much more now in my absence,) with fear and trembling work out your salvation which means to me that we can't save ourselves in line with For it is God who worketh in you, both to will and to accomplish, according to his good will. -- so the "being good" is in itself God working in us