Finally, now that I know that relationships are largely commercial associations

Yeah but that's not true. I spend time with people I enjoy spending time with, this goes for every kind of nonprofessional relationship. I'm now (in previous times I might have agreed some) baffled by what this even means exactly. There is a lot of giving in an interpersonal relationship, but it isn't commercial, any more than feeling good about yourself and the people around you is a commercial interest.

and that attractiveness, charisma and even happiness itself are mostly determined by genetics

Also not true. A most of being attractive (in both sexes) comes from how someone carries themselves, and how well they dress. Genetic things like cheekbones basically don't matter compared with self-care and conscious presentation. Any attractive male celebrity would look like trash if they stopped grooming and gained weight. The same is true for any attractive female celebrity.

it seems that even if I had the motivation to do everything right

You have motivation, a bunch of it actually. You just don't know what to do with it and it's banging around inside your head looking for an exit. I've been in the same place, and that's what I found anyway. Just start doing things, let motivation come later, and don't think too much. Case in point, you posted here, and you spend a lot of time on the internet. Those are both things which require motivation, which proves you have it, it might be a little stagnant right now though.

I would still more unhappy than average

Happiness isn't an objective scale, there isn't an average.

and if there is any truth to antinatalism, this means suicide is a must.

I'll be really honest here. You're just using antinatalism as a "rational" justification for suicidal feelings.

Even if antinatalism is true there is no philosophic requirement for suicide. Antinatalist thinkers say that birth is something to be avoided, but are not proponents of suicide (no famous antinatalists committed suicide)

Ok, advice. No one sees the world as it actually is, which is pretty unambiguous scientifically these days. The brain is filled with feed-back loops which tell it what it should be seeing. This is how people can miss objects when they look directly at them because they don't expect them to be there.

As such, your point of view really matters, as the world you create in your head, rapidly becomes the one you experience. At the level of brass tacks, your problem is ultimately that you don't have a point of view which makes the world seem good. This is a real problem, as this is the world you experience. The problem is, it isn't the world as it really is.

So what you need to do is change your point of view.

That's of course a lot easier said than done, as it basically means breaking some really well entrenched habits. So just break all your habits. You probably stretch your evenings late, and sleep in a lot. A lot of people do. Set an early absolute bed time (before 10 pm is better, as there's some evidence that digestion likes to happen around that time) and stick with it. It might take you hours to fall asleep the first week or two, but get that habit changed.

As you've said, you spend virtually all your time on the internet, so unplug, maybe all the way. Go walking instead, even if you don't live somewhere beautiful. Get outside and moving, both because it helps to shred your habits, and because it helps to get away from the world you've made by forcing interaction with the outside world. Maybe not walking, but do something that doesn't involve sitting down or looking at a screen.

Start getting exercise, most people don't really, so I feel it's a pretty safe bet you don't. You could get a gym membership, but all you really need is something like the /r/bodyweightfitness beginner guide. Hell, just doing various bodily exercises walking and stretching puts you ahead of the curve.

Eat different, which probably means learning to cook. There's a lot of recipes online for free, and generally it's possible to find classes in the local area.

This might be the hardest part, as you're always on for it, but change your thoughts. Realize that what you think is only that, and is malleable and not always connected with reality. You have a lot of assumptions about the world, (as seen above) many of which are simply not true in experience. Part of everything else is to help force you out into the world, where you can get closer to the world-that-is rather than the world you made up. I think you have a pretty good idea about what thoughts you ought to change, as they generally will be the ones which relate to fears and ideas about the worth of yourself and the world as a whole.

Lastly, don't neglect medicine and therapy for depression, as interpersonal and chemical means really help for disengaging from habits, as they have chemical footprints which you can also disrupt. As for interpersonal, humans are literally stressed out by being alone, and mis-percieve the world as worse than it is when alone. If you ignore everything else, this is why a good social life is important, so there's your answer. As such, it's really nice to have someone who is basically a stranger except that they listen and be there for you.

This is basically what I did when I was in a similar position coming out of high school, lucky for me my parents are therapist/neurosciency people, so I had the resources to figure this stuff out on my own. I'm supremely confidant that you will succeed in this, though I'm also super confidant that you're gonna suffer setbacks on the way.