Hi there Crazy - welcome to the SN board
Firstly I feel for you I've years of a child talking to himself and taking hours to go to sleep - as of today just gone down the medical route. However some things have worked on occassion for us which I'll list for you in a sec. I'm assuming your ds has no SN? ASD, ADHD, sensory issues?
Epsom salt baths really can help and cheap from the chemist - add to the bath 2/3 times per week
Move your bedtime until later
If he can't wind down then he's not producing enough of the chemical in the brain that helps us sleep. So any electronics need to off for an hour before bedtime - switch to lamps to dim lights etc. This helps the brain to produce melatonin which is the chemical that helps us wind down.
In our house we have a bed time story but on nights where ds is fractious I do the "quiet time story" which is something made up - basically ds visualises what I'm saying, so he starts in a forest and then finds a beach, swims with fish, then lies on warm blanket on beach and falls asleep, oh and the waves whisper sshhh. I'm sure you can come up with one for your ds.
Is your ds sensory seeking? Does he love and seek out certain materials against his skin? If so change his blanket to suit. Does he like to be squeezed? Maybe look at a weighted blanket?
Is he reliving his day when's he's talking to himself? Maybe change your routine so he has a story before bath, and then lie with him and tell him to tell you all the things he's thinking about.
Does he breathe okay while sleeping, it's just that my ds had an ENT issue that caused sleep apnea. Does he have any ENT issues? If he does GP can refer to ENT and they tend to run sleep clinics.
The last resort I would say is to give melatonin, which tends to be prescribed by a paediatrician. But you can also buy a spray online..... I say last resort not because melatonin is harmful but because it could be something that with a few changes you can fix. I would defo move that bedtime to 8pm though