Does “sin” apply to whether a person is “blamesless before the Lord”? I honestly don’t know the answer to that question, but Enoch and Elijah are said to have gone up into Heaven without dying…yet death is the punishment of sin. So it’s reasonable to say they never sinned, isn’t it?
Gen 6:9 (Noah is righteous and blameless before the Lord), Gen 17:1 (God tells Abram to be blameless before Him), Job 1:1, 8, 2:3, ect…(the whole book) (Job was blameless and God said so), Dan 6:22 (Daniel is blameless before the Lord), Lk 1:6 (John the Baptists parents are both blameless and righteous), Rev 14:1-6 (the multitude of 144,000 is blamesless).
If being “blameless before the Lord” suggests that the person did not commit personal sin, then it appears that there are several exceptions (that Paul would have known about when he wrote his letter to the Romans) and this was a general statement in Rom 3:23.