I'm turning 40 in a few days, heres my advice based on my own failures and some successes.

WORK

Don't pursue something you love as a hobby, because you will stop loving it as work. Exceptions to this are if you're naturally good at it AND it's traditionally a high paying field. For example, as a little kid, the weekly newspaper had a section containing house floor plans for sale. I used to take that instead of the comics, and id 'mark' them, pointing out what was good, and what was shit, and I drew hundreds and hundreds of my own house plans in meticulous detail as a 10-year old. I should have studied to be an architect. I would have lost passion for it, but at least I would have been naturally talented at it, which would have made my job easier, and therefore life happier.

If you are naturally talented at illustration, writing or another art, don't pursue that as work. Your passion for it will be destroyed and you won't be successful making a career of it. Instead, find something you're naturally okay at, and do that as a career. The only way to do this is by trying tons of hobbies, and losing interest in them. A lot of people pick up hobbies and lose interest and think they are wasting their time and failing. That's not true, they are learning about themselves. Keep on finding and trying new hobbies. You're not failing at them, you're auditioning them for the role, and most wont make the cut.

If you find that you pick up electronics easily, perhaps you should be an electrical engineer. If you can fix cars really well, shoot for diesel engineer. If you like boats, then maybe maritime engineering. If you are naturally very attentive to detail, like to be organised, and can convince people of things with your words, maybe consider lawyering. If you enjoy sculpting, then welding or civil engineering would be a good fit. If you love talking to people, socialising, making friends, doing banter, then there are a range of things that might suit you, Real Estate, public relations, sales rep. If you are of moderate to high intelligence and still aren't sure, choose a trade, like electrician, gas plumber, HVAC, solar tech, baker, butcher, cheesemonger. These have low barrier to entry, you can get paid to learn, and will always be an excellent backup option, and as a moderately intelligent person, you're going to already be in an advantageous position and will excel in the field.

Which brings me to backup options. Don't put all your efforts into one industry. As we see with the rise of AI decimating the software development industry, you can do everything right and still lose. I happened into this mindset accidentally. I started my working career as a metal worker machinist at 17. Then I started welding, and did that for 5 years. Then I went into the tech field as an IT grunt, on-call service tech in the hospital industry (nightmare), then I got into software engineering, then software design. During this transition I studied a completely unrelated degree at uni that is applicable to some rather specific government jobs and also worked weekends as a machine operator for an arborist and got my truck and EWP license. In a roundabout way, I became an architect by accident, just of software rather than houses. But if that went tits up tomorrow, I could easily get a job as a machine operator the following day, which paid almost as much, and I could look for a job as a welder, or machinist, or look for a job in the government sector I mentioned. I could even get a job in a bar because I have experience there and a liquor serving permit. Keep your options open, which leads me to:

EDUCATION

No matter how bare ass broke you get, education is the one thing the bank and repo men can't repossess. This makes it a good investment. As mentioned above, either study something you're naturally pretty good at and has prospects of a well paying job, or study something that definitively gives you options if your first plan goes sideways. It could be a uni degree, or a trade, or a certificate, just get something. Yeah it takes 2-4 years and that seems like a long time, but my dude, life goes on so much longer than that afterwards. The reason I didn't study architecture was because 4 years seemed like an eternity when I was 20, and I was afraid I would lose interest in it. If I had known that, yes I'll lose interest in it as a hobby and end up disliking it just like any other job, BUT I'll find it easy because I'm naturally good at it, this would have changed my whole mindset. Make your working life easier.

Education doesn't stop at university. Where possible, get employers to upskill you. If they won't, do it yourself. Occupational First aid, forklift license (unironically despite the meme, I drive a forklift sometimes in my day job as a software architect when the warehouse staff are all absent, and it's so much fun), truck license, alcohol serving permit, chainsaw safety, EWP, Hiab crane, open cabling (network and telecoms), whatever piques your interest. Some of these are required licenses, and others are just optional training, but both types are useful. These sorts of courses take a couple of days, cost a couple hundred bucks, but you'll have the education for life. You might even find a new thing you're naturally good at or meet fun people. Have I used my boat skippers license once since I got it? No, but it was a hella fun way to spend a weekend and $200.

SEX AND RELATIONSHIPS

Holy hell this one is a resource drain if you let it be. Boys, girls, gay, straight, nobi, trans, Polytechnic, only the Aroace get a reprieve from this one, and even for them, there is much to be lost here.

Sex doesn't matter, and it won't make you happy over any sort of timescale. Sex is like doing a whippet in the backseat of your friends hyundai behind a closed gas station, you'll feel nice for 10 minutes before the regret sets in and you ask "What the fuck am I doing with my life?" Before doing another whippet to escape the shame. Unfortunately sex is a base biological imperative for most people, and it will make them stupid things. I'm not immune to that, but with age, I have developed through experience and exposure some resistance towards the impulse to do dumb shit and squander money for that next whippet.

A fulfilling relationship has many facets, and sex is one of them, but a small one, and in some cases the sex facet can be a barrier to success of a fulfilling relationship if expectations are not aligned or honestly is not being practiced. My advice on relationships might be controversial, but you should not be seeking someone who makes you happy or someone who completes you. It's not someone else's job to fill in gaps in your life that are lacking or that you haven't or aren't willing to work on. Each person should bring to the relationship the whole of themselves without expectation of getting a crutch to lean on, because this leads to asymmetry, unmet expectation, and resentment. An asymmetry might develop or become apparent, and that's ok, but it is then the responsibility of the person with the weakness to work on improving themselves and the responsibility of the.person being leaned on to communicate expectations and boundaries. If one person loses a job and becomes financially dependent on the other, that isn't a reason to end a relationship , in fact it can strengthen a relationship and spur personal growth on both sides, learning humility, gratitude, strength, compassion. But if that dynamic lasts a long time, or if the unemployed person doesn't make any effort to reduce their dependency, then resentment will seep in.

I recommend this short read, The Abilene Paradox, to better understand expectation, resentment and what happens in interpersonal relationships when honesty is missing:

https://en.wikipedia.org/wiki/Abilene_paradox

DRUGS

Try them if you want, but recognise their hazards and your own weaknesses. Most of my friends were heavy drug users, including cocaine, meth, and heroin, most were alcoholics. All of us are over 30 now, and all of us are clean and sober, and happier for it. If you think you're becoming habitual or dependent on a drug, try to catch it early, go to a meeting, talk to a psych, read trip reports for 8 hours, whatever you can do to build your own awareness and cognizance of its dynamic in your life. Again, this will be an unpopular opinion, but if you thing you are even slightly dependent on alcohol, don't wait 15 years, get help right away. It doesn't have to be an AA meeting, but they are free after all. Detox and Rehab is very expensive.

Lastly, the world is not going to end, even though it feels like it will. I felt that way all my life. Why bother committing to anything when the only useful skill I'll need is scavenging food scraps and hiding from roving bands of cannibals in a radioactive wasteland. It took surviving multiple once-in-a-lifetime catastrophes to realise "oh, the world's going to keep on going, and it's going to drag me with it if I don't walk." Don't let the deep apathy in forever, dip your toes in if you need to, but then get on with your day.

Hope that helps in some way. I have a lot of regret in my life, but most of it is either repairable or teachable. Its ok to look back, but it's rude to stare.