In an ideal scenario you would quit working entirely to focus on your health, but I’m guessing this is not an option.
You need to focus on the body first. The most important is sleep, but that is also difficult to address directly, so it’s best to focus on diet and exercise. You’ll likely have to design your entire day and week around these two things.
Try the Whole 30 program first. It’s a way of eating that eliminates inflammation causing foods. DONT TRY TO LOSE WEIGHT! Weight loss is important for overall health but you’ll usually sleep worse during a weight loss phase. That said you’ll probably lose weight naturally anyway.
Give up the alcohol for 30 days and consider weening off caffeine at some point since both of these will mess up your sleep.
For exercise, you just have to find something enjoyable enough to do at least 3x per week. It really doesn’t matter what it is as long as it makes you a bit sore. Consistency is key - don’t overdo it by jumping into something like CrossFit.
Lastly, WHY are you burning yourself out? Are you afraid of failing? Afraid of being broke? Afraid of being perceived as a loser? The WHY is a spiritual problem and may be addressed through meditation (slow), psychotherapy (slower), or psychedelics (fast but more risk). Until you resolve the WHY of your burnout you’ll likely remain stuck in this cycle.