Tiredness would not be a symptom of to much oestrogen and on Estradot 50 mcg you are not likely to be getting too much. Palpitations are also a sign of low oestrogen (but also things like too much caffeine or alcohol!).
I'm in my mid 60's too and I get very tired - especially in the mornings despite being on a decent level of oestrogen and testosterone too. I think there are other factors at play as we age - in my case I've no idea - bit something is amiss with my cortisol awakening response (it doesn't happen).
If you are tired during the day then this could be due to all sorts of things - low testosterone, low oestrogen, sub-optimal thyroid function. low iron, some vitamins, insufficient exercise, inadequate quality sleep, excess weight etc...
Like you I dread the progesterone phase due to increased tiredness - hence the long cycle! Hope you cope with it OK!
Hurdity x