There are lots of great ideas and thoughts from the others here, so I won't focus on the same things that have already been mentioned.
You mention a few different issues, feeling burned out, health, and not finding the work interesting. I think you should focus on those three individually rather than trying to find a single silver bullet.
First, take care of your health. You can start by doing some simple things: eat better, have a better sleep schedule, go on more walks and slowly build up to what you expect from yourself and feel that you're missing in this regard. It doesn't have to be spend 2 hours/day at the gym starting tomorrow.
Second, with regards to feeling burned out, think about what your ideal situation looks like. If you had unlimited money, what would you fill your time with? Next, think about if you had a lot of money but still couldn't have the security of financial independence/freedom. What would you do for income? The point here is to determine two things: 1) what's enough for you and 2) what your passions are. It's ok to do things type not passionate of to sustain yourself/family, but you'll eventually feel burned out trying to get more than enough. Determine what enough is and to what end you'll do things that aren't your passion.
Lastly, about not finding your work interesting. This is totally normal. It's hard to find your passions interesting over decades. Passions change over time and that's ok. Are there things you do like about your job? My previous point about thinking about your passions applies here. It may be you hate the environment or dislike being told what to do. I love writing software, but dislike a lot of things about modern "industry best practice".
Hope you find what you're after and enjoy the journey as much as the destination. Life is too short and you never know how short it really is.