Testicular atrophy is from exogenous testosterone usage. Your body detects that it no longer needs to produce its own, so your testes shut down (see FSH and LH in blood panels). HCG is what is commonly prescribed to instruct your body to continue producing its own testosterone despite the presence of exogenous versions.
High estrogen and low estrogen symptoms have similarities and differences. Loss of libido and erection difficulties are present in both scenarios. Typically joint pain is an addition when it’s a low e2 issue (amongst other things); and high e2 will show through acne, excess water retention, high bp, gyno, and crying through Frozen after watching it five times straight.
Symptoms are not linear, so you need to rely on your own personal bloodwork.