Paul was talking about his pre-conversion self in Rom 7:21, and not his post-conversion self.Paul gave us all a very exacting Spiritual Transcription of every law or command in the entire Bible in Romans 13:8-10
IF anyone reads any law, and can't figure it out, they need lessons from the Holy Spirit
In any case, Paul essentially also guaranteed us that the evil present within no one is going to be following any law, no matter how it's written, Romans 7:21
As Paul wrote in Rom 8:2..."For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death."
That is his post-conversion self.
Free from the law of sin and death.