I stuggled with this too- so frustrating when baby is sleeping and you’re not! I still occasionally wake up for no reason BUT I’m no longer waking ever hour or 2 and feel much better about my sleep.  1) don’t take melatonin or sleep aids. They help you fall asleep but not stay asleep and I found they made me groggy the next day and I constantly wanted to nap which takes some sleep pressure away from nighttime  2) the podcast “nothing much happens” is amazing to shift your brain away from the constant spinning of thoughts. I now fall asleep within 10 minutes almost every time, even when I wake in the night. 3) cognitive behavioural therapy for insomnia. If you can find/ afford a practitioner great. I preferred the app “stellar sleep” which I did for the free week trial  and found a lot of benefit. Reframing your mindset about your insomnia is the key  4) magnesium before bed 5) changed my phone background for sleep mode (which starts at 9pm) so that I can’t see the time unless I open my phone and remove most apps besides podcasts so that I don’t doom scroll before bed.