Thanks for your help.
Although I would like to say that everyone I have spoken to about this, throughout my career, has assumed that I'm just going through a period of burn out. I've been unhappy with my career for 10 years and the resentment and discontent has only grown.
In fact it was people telling me that I just needed to regroup and watch for burnout that kept me in the job. I listened to people when they assumed the problem was manageable and would go away.
But you see, when there is a fundamental disconnect between you and your career, you cant just wish it away. It grows and grows and eats away at you.
For me coding is an irritating, depressing, meaningless activity. The only thing that makes it worthwhile is the thing that is being created. But when you are employed as a coder making something worthwhile is not an everyday occurrence. And tbh even if I was building the most meaningful product I could imagine, it's not enough to keep me engaged. Writing code it just too unpleasant.
I would have been much better to quit when I first realised that this wasn't for me, rather than wasting a decade of my life trying to convince myself that I could make it work.