Have you tried a protein treatment? If you use CJ products, you may like CJ Repair Me!
It's great as PT and it's moisturizing enough so you don't need following with a DC.
I think you need a product like Jessicurl Confident Coils. More than definition, you need frizz control. If you want more definition, you can add Jessicurl Rockin'Ringlets. But also KCCC is great!!!
Oh, itchy scalp! I can understand you.
Maybe some ingredient in some product is too aggressive for you. Try SM Black African line. It's for itchy dry scalp.
Let me know!**