Why can’t disappointment and grace coexist? That doesn’t make sense. It seems more normal to accept that God is sad when we sin and happy when obey, and we should respectively feel sad and happy about our sins and obedience. I like that you want to help people not sink into useless despair, but I don’t think it’s necessary to redefine the words “shame” and “disappointment” as extremes. People can be ashamed of their sins, and then get over it through faith and grace. God can be disappointed in us for sinning and also forgive us. I think it’s better to emphasize that being overwhelmed by shame and self-hatred is a sign that one should strengthen their faith in the grace of the atonement. If shame is not a result of faith, then it is in vain. Faith should predominate repentance. Shame and disappointment are basic aspects of repentance in the Gospel.