Your post really resonates with me, OP, having faced a similar existential crisis myself a few years back. I'm a guy and currently work in a very blue collar but well paid profession (trucks and onsite lifting machinery) but my general dilemma was very similar.
Came from a middle class background (mum a teacher and dad an executive for a big banking group). Got a good degree from a decent uni and landed a fairly decent office job in corporate sales/proposal management. Was making £35k in my early 30s with company car and good benefits package. Not crazy money but was on fast track to be a Senior BDM which would make me about £65k OTE within a few years.
Ticked all the boxes but just didn't feel right to me. Like you, I was single with a good group of friends and a decent quality of life being situated in a fairly 'cheap' part of the UK.
I always hated the airs and graces of corporate culture and having to 'play the game'. After getting made redundant along with most of my team, following our division making a loss, I decided to get my HGV license. I did some crap jobs to get experience but was back on £35k within a year. Another year on I'm now on £40k.
At the start, I often reflected that I didn't have the same prospects as I did in my previous job, but tbh I absolutely loved being able to escape the corporate crush/rat race. It suits some people but I hated the disingenuousness of it all. People getting promoted based on how well they presented their achievements rather than their actual productivity - a common issue when working in large teams where the senior management aren't able to gain an accurate overview due to the complexity and sheer volume of work output.
In my previous job I had the lure of an ever better salary but my day to day existence was bleh. Nowadays I drive to work with a clear mind and I don't have to contemplate what I'll say in conf calls, meetings, etc. I'm able to live in the moment for the most part. I occasionally wonder wtf I'm doing driving a 70t truck with a 1st class degree but then I reflect that there are many people earning less than £40k who have a much more stressful day. As long as I don't drop a 10 ton bit of metal on somebody I'm good. I never have to justify my work rate to the office as I'm the expert and it's my license on the line if somebody gets hurt.
My father came from an extremely poor background and managed to drag himself out of his circumstances through hard work and education. I originally worried he'd be ashamed of me for not following in his footsteps but it was all in my head. I'm in the process of upgrading my mobile crane experience and that will open up a lot of doors. £65k is easily achievable in a few years with hard work, and over £50k is almost a certainty. The top guys are on £85k and are almost exclusively self employed. They generally travel all over the UK and often have to stay in a hotel for a few days, waiting around just to complete a single lift which will be fairly quick but extremely precise, lifting objects up to 1200 tons.
Most people I know thought I was mad leaving a good office job with career progression to train as a trucker lol, but it's improved every aspect of my life as I'm not constantly bogged down with admin and mundane phone conversations. I'm able to switch off when I leave work and not give it a seconds thought until I next walk into the depot. I think you need to forgot about what other people think and find your own way. I still have to nod my head and be polite to mr pointy shoes when I arrive at a new client site for safety induction. However, despite no longer wearing a suit and driving a company bimmer I know this guy in a high vis will be on £85k in a few years and still not worrying about conference calls and how to conduct myself in meetings like most people on a decent salary have to.