You are living the dream, I suspect, from a UK perspective. I have a similar background. Not sure what you mean by coffee engineer? I have friends who are plumbers (gas safe) or builders etc. They can make the same money as me, or more, but it's hard work and you have a lot of liability on you. You also need to manage the business side as well as the work, if you want to be self employed and hence make decent money.

Despite being very sporty, I'm now finding in my mid 40s that I'm hitting various physical issues. Nothing serious, but would prevent me from doing hard manual work every day. As it is I haven't lost a days work due to pandemic, or illness for years now as the work I do is so low impact and from home. I imagine this would be much more challenging into 50s and 60s whereas in tech you can work almost indefinitely (I have a friend about 75 who is working).

You also need to consider the training and certification time that might be required. Also being out on the road wouldn't work for me, I'm used to being close to home now.