I can still feel the adrenaline and elevated heart rate and body temperature that just makes it even more difficult to fall asleep so I have no idea how people who go to the gym at 9PM manage to fall asleep. I wish I knew their secret or had their genetics.

Lighter exercises that don't stress the body, like long walks and yoga are much better for sleeping but not good for building muscle.

My problem isn't falling asleep, it's staying asleep for long enough to feel rested. I usually wake up after 4-5h and can't easily fall back to sleep. By the time I get sleepy again(7-8AM) it's already morning and time to get up for work.

So far I haven't found a (natural) cure for this. There's medication that aids with getting long sleep but the side effects (drowsy ness and brain fog) are nearly just as bad as the lack of sleep.