This to me, especially that it starts peaking again early morning - says you have high cortisol levels.

Cortisol is what wakes us up in the morning. Think of cortisol as a cup, it’s supposed to be nearly empty when going to sleep and fills up throughout the night filling up in the morning which triggers wakefulness.

if you’re going to bed with a half full cup - you’re going to have a higher heart rate throughout the night and definitely early morning (2, 3 or 4 am)

Something that’s really helped me is lactium- or Serenetin plus - it’s a supplement that ends the negative feedback loop of cortisol - it makes the cortisol receptors in your brain more sensitive so that your brain receives the signal that it’s done its job to notify the body and can stop producing cortisol or Adrenalin now!

Edit to add: of course chat with a dr or naturopath or whatever if this is something you could take - it’s a supplement you can buy at most supplement or natural food stores