This was my experience with TRT, too.
On weekly injections I always found that I felt the best a day or two before my next shot was due, around 650 ng/dl. Then, a day or so after my next injection when levels hit > 1000 ng/dl, erections and libido would disappear again, water retention would go up and brain fog would return. As I moved to a higher injection frequency and higher levels were kept more constant, my sexual function was lost outright.
Deep down I always knew that I felt better at lower level, but I didn't want to believe it. Everyone thinks that they can make extremely high levels work - mainly because they think it'll confer them an 'advantage' over naturals re: muscle, sexual function, energy, etc - but for most, it doesn't work that way.
Instead of acknowledging that it was the high testosterone itself causing the issues, I instead looked for scapegoats in estradiol, HCG, adrenal hormones, etc, as the cause of all my hormone-related issues. In reality, the real problem was staring me in the face the entire time, but I chose not to see it.
Years of time and energy wasted due to that mindset.