What is wrong with my hair?

What is wrong with my hair?

From the gross picture, it looks like Diffuse Unpatterned alopecia (DUPA) but I would have to examine you with a trichoscpe to make the diagnosis and what I would see is significantly more than 20% of the hairs miniaturized in the back and side of your head.  Am I correct that you have not had FUE surgeries?  See here for photo of DUPA: https://baldingblog.com/do-i-have-dupa-photo/