Help! I am 3 weeks in and I don’t know what to do!

I have VERY thick, curly hair that is often dry on the ends and oily at the roots. I have been doing the baking soda/apple cider vinegar technique for three weeks. My hair hasn’t looked or felt good the entire time. It is either very dry or very oily. I am washing (with baking soda and vinegar) about every two to three days, rinsing daily. I can barely brush it, it is so knotted and tangled. I can feel the residual baking soda on my hair, even after rinsing throughly. I can’t do anything to style it.

Any help? Thoughts/ideas?