My situation:

I’m 27 and I have …
Crooked front teeth.
A fairly significantly inward leaning lower left canine.
Deep poorly drilled, poorly filled cavities on nearly all rear 8 molars.
An untreated cavity on my lower left premolar.
Have never had my wisdom teeth removed – but never had a dentist cite them as problematic.
My teeth are tightly packed with rear molars being pushed inward, and a front tooth being pushed outwards. Making my palette feel small.
The curve of my upper teeth on the left is different than on the right which curves in towards the middle of my mouth.
My teeth have not had a single position to bite or sit comfortably since I was 10.
I’ve gone through long bouts of discomfort and pain which I would call compactions, but have been brushed off by dentists when I’ve brought this up.

I’ve had many unpleasant dental experiences, including very unprofessional treatment from a Private dentist as an NHS patient when I was 16 which led to my parents cancelling me getting braces.

The state of my dental health has probably ruined my life, it plays a large part in causing depression that I end up trying to hide as much as I do my teeth. And I literally cannot take it anymore.

My question:
I feel that my dental problems have also caused my jaw to recede, and I’m scared of moving forward and be given an inappropriate dental only solution to what could be a larger problem.

Where do I go, who do I ask and how do I take the right cosmetic first step?