You make some excellent observations @Finfina Myself and others have had similar pattern while being on AI. Libido would usually spike when starting AI and dampens later with continued use as E2 goes very low and T (and LH) goes out of range high. My guess is that as E2 declines (with AI), the body increases LH, which stimulate gonads to produce Testosterone so that it can be converted to E2 to restore its former level. During this process, the sweet spot for T:E2 is achieved and hence causes libido to surge. Some AIs (like aromasin) also happen to lower SHBG, which frees up more T, E2 & DHT.
Note: I’d never touch aromasin ever again because I think it may have permanently lowered my E2.
Cortisol remains to be such a challenging hormone to understand. For starters, it regulates blood sugar, governs thyroid, involved in energy production and acts as anti-inflammatory (again immune system) among other functions. I’d guess that without adequate energy then cellular processes are impaired. I’d read somewhere that when there isn’t enough cortisol, the body compensates with adrenaline (i.e. panic mode). Adrenaline is made by conversion of dopamine. I get high adrenaline when my blood sugar gets very low. When this happens during sleep, I get night sweats and night awakenings and thus unrefreshing sleep (i.e. low Testosterone & HGH produced). It’s a vicious cycle.