what is your obession with DHT? Serum DHT isnt even all that useful. Often times serum will come back low but 24 hour urine panels will be twice the top of range.
I promise you your DHT is high enough that its not causing your symptoms. While it may not be "optimal" its more then adequate.
Not to mention i have never heard of any way to raise DHT except to go on TRT , and more specifically androgel which has an affinity to raise DHT.
But your not gona go on TRT since your testosterone is not bad so mute point.