I do all that stuff, and more. Thank you, but it doesn’t help much. One one thing that helps is not having any screens or audio in bed and waking up at the same time every day. The latter is excruciating for me.
I was told that alternating cold and hot showers - a few cycles - help reset the nervous system. I tried it a few times and seems to be working, makes me feel relaxed and tired in a pleasant way. Simply taking cold showers before going to bed will make you feel invigorated, not very conducive to sleep.
Yes. You can finish with hot. Make sure hot/cold water get all over your torso, chest and spine. You will feel really good afterwards even though the cold water isn't very pleasant.
Alternatively, in the summer, take cold showers for invigoration, especially if you feel sleepy in the morning. It is unpleasant for the moment but it makes you feel great afterwards.
It was mentioned in Tim Ferris' book so I tried it at the time, considering I was living in a tropical country at the time, so the cold definitely helped get to sleep. I just checked once more and he mentions a Stanford University professor's quote on the same.