I suffered from the same thing for years. Now I live somewhere that is quiet: my neighbours still wake me up but there isn't the same anxiety about it.

I agree with you that it's a somatic problem and needs to be understood on the level of brain/ nervous system malfunction. I was struggling terribly with it at one point in my life when leaving home early and working long hours. I can remember trying to sleep on the floor of the hall of my house so as not to hear vibrations.

I decided to practice sleeping, to train my body to re-member how to sleep. To take every opportunity to reinforce regular sleep. Tai chi exercise to slow down before sleep. Soft toys. Acoustic musis. A warm drink handy nearby. DJ earphones.

Moving to a quiet place was what solved it. Because mostly I'm not woken up. If I do get insomnia - I have it bad at the moment - it's an exception and I get a script for sleeping tablets for a few days.

I've had some crazy conversations with doctors about this in the course of my life.
I try to have routines that promote sleep. When I'm living alone in the house, I try out different bedrooms lol. My bedroom is for peaceful things: problems get left downstairs in the sitting room. I have a burglar alarm so that I know I will be woken if there is a real emergency. I try to actively listen for birdsong or quiet soothing sounds.

Everything in my life prioritises regular sleep routines because if I go without for a day then my body forgets how to sleep all over again. Where possible I warn house guests that I need quiet after a certain time in the evening.

No solution, just my experience of struggling with this. It's a serious problem if you have work commitments.