Hi
Im 52 and been on TRT for 18 months. It is likely your high E.

Ive tried anastrozole and Letrozole for AI. I have stuck with Letrozole and use a liquid so i can accurately measure small doses.

After 250 mg a week T, i need AI definitely; i also use HCG which seems to help with libido (but only if your E is ok)
I react to AI doses within 24 hours, might take half a week if i let E get too high, to come good though.

If I'm consistent i dose letrozole between .15 and .25 mg's, you can take your E very low with letrozole, so you need small accurate doses. (every 3 to 7 days depending on how i am dosing T)

Log everything and write notes on how you are going, after a while you see comments and dose against blood tests. That way you learn about yourself.