An interesting thought experiment for you, David, and nothing more:
How would a traditional fundamentalist react to the following idea?
If Jesus is the way, the truth, and the "life," and the author of morality is also Jesus, as we both agree, then can we benchmark each of these listed sins by the interference they cause in the life cycle?
We are curiously part of some kind of divine AI-like experiment, although Judeo/Christian religion doesn't frame it that way. God is doing something unique that we don't fully understand. Whatever that is, some of us will pass the test, and some will not. Stripped of the religious terminology, perhaps sin is simply the attitude of rebellion in us that makes us spit on and squander the valuable gift God gave us; life. Every aspect of creation, salvation, and resurrection points to the furtherance of life, so it's not a stretch.
Life is clearly sacred.
Maybe sin is anything that interferes with the fullness of life or decisions we make that stop the life cycle. In other words, sin is more than a stinky attitude toward God.
For example: Is suicide a sin? Or how about abortion in most cases? In the above light, maybe so because it stops the life cycle. This part of God's experiment fails due to our free will choices, and He is not happy about that.
Or how about spousal abuse? Violence or verbal assaults can break down the family unit for generations, causing the fullness and furthering of life to struggle and fail because of familial dysfunction. This type of abuse is cancerous and regenerative. It may not cease life instantly but instead can cause the victim's life to suffer for years or decades, stunting lives planted in bad soil.
What about drug or alcohol addiction? In moderation, perhaps a beer won't send a person to eternal damnation, as I was taught while growing up in my Southern Baptist church eons ago. But maybe it's a sin for some because of alcohol's destructive nature within their unique bodies and how it affects their minds. Alcohol suffocates life in their case. So maybe I get a free pass, but they don't for those factors.
Only God knows the rules of His experiment, and I'm certainly not in God's head, but when I take demons and the devil out of the language surrounding sin, I start to understand what it is, and I also gain a better understanding of what God may be up to.
FWIW, I do believe in angels and demons. I just don't think they are behind every bad choice we make.
But I do believe we are in a cosmic test of our free will. Will we choose life or death? Recognizing our creator is the first correct answer on that test.
Also consider, why would God want rebellious, self-destructing humans as part of His future plans in heaven. We will have free will there as well. Didn't He learn anything from the fallen angels rebelling against Him the first time around? Haven't they caused enough damage? Do we really need a sequel to this story? No way.
The above is all speculation, of course, but I am curious about your thoughts if you find this interesting.