EQ can bounce back and forth with any PE exercise, yet I think especially hanging. The variance is to be expected. However, massive swings (downward) are strong indications of overwork and need to be heeded as feedback before injury. At the same time, EQ is not always about PE efforts. It has many variables, so a person has to rule those in/out as well. It is really about good analysis.
I have had heavy workouts followed by intensely stiff wood when masturbating later in the evening (a few hours later). Alternately, I have struggled to get hard enough on some days when I haven’t been able to PE and other factors are in play.
There is no one answer. PE = getting to know your body and unit over time. There is absolutely no substitute for it, no magic post, no item to buy. Yes, read - gain insight. But in the end, there is a massive time factor. Also, learn about overall health and what physiological elements are involved in a male erection