I've always been a poor sleeper my whole life and have tried many different things. The anxious self talk is very destructive to sleep habits as you've said but is so "natural".

Over the years, I've developed different ways of coping with it. When I notice I'm heading down that path of "If I don't fall asleep now, tomorrow will be horrible" etc, I replace it with things like:

"It doesn't matter if I sleep right now, its only one night and I will do ok with a bit less sleep."

Then I start to really think about my individual body parts and how they feel.

"My feet are nice and warm and feel so comfy resting on the mattress" and really feel my feet.

"My knees and thighs sink deeply into the soft bedding, that feels so nice".

"My back is so supported and relaxed"

And if I come to a body part that isn't in its most comfy spot, I think about that too and think maybe if I shift a tiny bit this way it will be nicer. Or if I tuck this pillow like that.

I think really focusing on each part and its comfort and how the sheets feel and the softness makes me really relax, calm down and fall asleep quickly.

By the same token, if something is really uncomfortable (like the dog accidentally got upstairs and ate a cookie in the bed leaving crumbs!) I get up immediately, change the sheets and try again. Otherwise, all I can think about is how prickly things are

Not sure if that will help you, but that has improved my ability to ward off the negative stressed out "must sleep now" thoughts that don't allow for any sleep.

Starr