I've got chronic insomnia.
Something like this helps a lot. The magnesium and the 5htp in particular:
Numan Sleep Deep - 60 Vegan Capsules with Natural Melatonin Sources, 5-HTP, Chamomile, L-Theanine, Magnesium - Natural Sleep Aid, Stress Relief, Relaxation - Sleep Supplement Tablets - Made in UK https://amzn.eu/d/9wM3PsZ
These are also good if you play white noise or ambient noise through them:
Sleep Headphones Bluetooth Eye Mask,Wireless Music Sleep Mask Ultra-Soft Sleeping Headphone Comfy & Washable Perfect for Side Sleepers/Office/Travel,Birthday for Men Women https://amzn.eu/d/fUkL6A1
I recommend something like this to listen to:
Make sure you have good sleep hygiene. You want it dim most of the evening. If you can just have fairy lights or a dim lamp on alone, that's perfect.
A bath or a shower before bed is useful. If it's a bath, try some lavender products.
Keep it nice and cold in your room. You want it about 18 degrees. Or I find even colder helps, as long as you're warm in bed.
Racing thoughts can be interrupted with an audiobook. I find it's really nice to read until your eyes get tired and then stick the audiobook version on.
If none of that helps, Nytol one a night capsules in the blue packet are helpful for short term insomnia, although they can cause restless legs. If even that isn't working, you might need some actual sleeping tablets on prescription for a bit.