I don't know if I'm exactly the right kind of experience you're looking for, but I'll give you what I got!
I'm in my early thirties, not forties. I left my desk job for my crafting business (soapmaking), which is certainly a manual trade but also not what people typically think of when they consider 'manual labor.'
First, the trade offs: I make VASTLY less than I did at my office job, and I wasn't even making all that much in the office. Maybe that gap will lessen as my business grows, maybe it won't. That's a gamble. Working with your hands can be HARD on your body, especially if you're not accustomed to it, and I'm still fairly young and in relatively good health. I need to take more care with stretching, regular massages, not overworking myself, wearing arm braces, all of that. I won't mention health insurance since I'm US based, but only to say that you have to be careful not to damage your body in a way that will negatively impact your life when you're older.
I don't know if you want to go into business for yourself or work as a [tile layer / gardener / woodworker etc.] for someone else, but both have their positives and negatives. If you choose to go into business for yourself, then you also open yourself up to the whole small business operations aspect of things - namely, bookkeeping, invoicing, collecting, business registration, marketing, regulations, customer service, and on and on. All of those things can take up as much time or more than the actual 'manual labor' aspect of your new career.
You have to be disciplined in a way that you don't have to be when you're working as an employee at a desk job. Not to say that desk jobs are some kind of 'do nothing' work (I worked myself to horrible burnout at my old job), but I had days when I slacked off and didn't answer any emails or work at tasks and nobody noticed because I could spread my work around and prioritize as needed. When it comes to a career 'doing and making', either the work is done, the product completed, or it isn't.
The benefits: Am I happy with my choice? Yeah, I love it. I love being in business for myself, I love sleeping in and working late and doing whatever I want whenever I want with only myself and my work to be accountable to. I do like and enjoy the small business aspects of what I do. I move around a lot more during the day, I'm not chained to my desk. There are stressful aspects of my work now, but none of it compares to the stress and dissatisfaction and grinding unhappiness I held back in my desk job.
At the core of it, I find a LOT more personal fulfillment in 'making things with my hands' than I ever did tiptapping away at the computer and taking phone calls.
