Two different types of hair?

Hi! I am trying to figure things out... It seems I have fine top layer of hair, that curls well and looks great. My underneath hair can look straw like and not curl as well, sticking out the bottom looking stringy. I was reading on the protein sensitive board and feel this could be my issue? Anyone else have two different types of hair and how do you treat them differently?
Curl Type- 3a, some 2,
CO Wash- Sauve Conditioner or Loreal sulfate free cleansing conditioner
RO- Generic Biolage Conditioning Balm
LI- Kinky Curly Knot Today Leave in conditioner
Styler- Curly Hair Solutions Curl Keeper
Gel- Garnier Fructis Pure and Clean
CO Wash- Sauve Conditioner or Loreal sulfate free cleansing conditioner
RO- Generic Biolage Conditioning Balm
LI- Kinky Curly Knot Today Leave in conditioner
Styler- Curly Hair Solutions Curl Keeper
Gel- Garnier Fructis Pure and Clean
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