It's very hard to give advice in general. That's why the wise teachers used to mentor mentees one on one, there's little wisdom that applies in all circumstances. Advice expresses a direction, and if you are already too far in the other way, you need to be pointed backwards.

If you think all it takes is willpower and you force and force till you break down and conclude that you're just worthless, then you're doing it wrong. There is a sense in which self-improvement as a concept is bullshit, in the sense that Alan Watts expresses here: https://www.youtube.com/watch?v=vlNVQ-_y4-0

Ultimately nothing is "deeply broken" in some metaphysical sense in this universe. When we say something is "bad" it just a shorthand to mean we don't want it to be like that. It isn't bad deep down in the fabric of the physical universe. The universe is very aloof and unresponsive and ignorant of what we want or not. It's not trying to spite you when you fail, it just doesn't know what the hell we want from it. When my shoes get dirty, it's not because the world has decided to spite me and make me angry. Reality has no concept of "dirt", it doesn't know that I didn't intentionally scoop up the dirt with my shoes while walking. It's the same mechanism that we sometimes use to intentionally get sticky materials onto a surface. The way to communicate what you want from reality is through action, because that's the language that reality speaks.

The whole self-improvement business has to be done in an intricate balance between taking it playfully and taking it seriously. This is really hard to express properly in a comment. Ultimately you will always have something else to desire, something else to work towards, nothing will be ultimately and finally satisfactory unless you also work on your mindset.

But there are better and worse states of being in some sense. Having anxiety, depression, insomnia, brain fog, addiction, obesity etc. is in some very real sense worse than being fit and in a good mood by default. With the caveats above.

Making people want something is almost impossible. Nobody could ever make me exercise a few years ago. It was just not part of my identity. I thought the gym was for just for loud tough gym bros on steroids looking to get more one night stands. Blog posts and articles like this slowly accumulate in the back of one's mind. And when shit gets really rough and you by yourself come to the realization that you will now do something. Not because you have to or it's your duty or because anything, but you just know that you will now do something because you know things are not going well. Then if you stored these tips up, you may say, you know what, I'm going to actually try that thing I've read about so much in the context of mental health and depression. You will have something to reach for.

Sure there can be other underlying causes for why your life is derailed. But first and foremost you need to fix yourself as a biological homo sapiens to a certain level so that you can engage in the complex task of untangling why you slid off the road. (Beyond a certain point you need a therapist clearly, but only beyond a certain point). Once you have the mental clarity and energy and a baseline okayish mood, you can think of what lead to all this. Maybe you're giving 200% at work, trying to satisfy everyone, while others are actually taking credit for your work who work way less intensely. Maybe you're pushing hard at work to become a martyr and aren't actually using your energy in an efficient manner and others are more ahead because they are working more efficiently not harder. Maybe you seek validation in your professional life because your intimate relationships are failing. Why are they failing, why do you have no friends, are there perhaps practical issues involved, do you commute too long, could you move closer to places where socializing would be easier etc etc. But you cannot begin to tackle these questions is you're in the loop of rough sleep, tons of caffeine, 200% hard work for someone else, stuffing yourself with ice cream and chocolate at home alone, then binge watching stupid youtube videos while downing beer after beer, staying up late, and repeating the cycle.

Don't question it with 23 additional meta levels of buts and ifs and counterintuitive speculations that it will then mean that I am X, Y, Z. Or that it will mean that I should have already done it. Or that I have to admit something or judge myself or I won't be able to keep it up, that I tried so many things already or whatever. Too much thinking. Just do it, shoes on, no thinking, go for a walk/jog. Care for your biological animal side. No questions, you don't need to rationalize it, you don't have to have a great scientific explanation. There can always be questions and doubts. But fixing basic lifestyle will be beneficial. There's no way you're going to end up worse by fixing these. I found it to be very beneficial to read Zen texts and koans and listen to Alan Watts to stop the destructive thought loops and realize their absurdity.

But surely, sometimes all it takes is not conceptual intellectual advice, just a hug, a gentle look, a soothing voice etc. But an article cannot provide this by its nature, so it will be about practical, conceptual things.