Hey Victor, Maddie here. I get where you are coming from, especially the frustration that a) you aren't being understood when you say you want to stop needing or desiring interaction with, and validation from, other people, especially since from your perspective, that needing and wanting has only increased your pain and made it harder to isolate yourself so you can feel safe(r). And b) if they do hear you, that no one has real suggestions about how to stop caring.
I have quite a but of personal, practical experience with what you are seeking. It is quite attainable if you have the discipline to study, to practice, and to not give up. You have your choice between three major traditions of mindfulness meditation, that have millennia of successful track history of helping individuals to let go of their wants desires and neediness are concerned, and to learn to take people as they are, not needing or caring for them to act any particular way, or be in any kind of relationship with you.
The traditions fall under the Vedic/yogic schools, the various Buddhist schools, and the various Taoist schools.
I personally have had the best results with the Zen/Chan Buddist meditation, leading me to the Taoist water school for advanced practice, but you would probably find the meditation practices associated with the martial arts more resonant with your masculine way of seeing the world.
It has given me an enormous amount of relief, while letting me stay clear headed and safe, because I own my thoughts and emotions, they do not own me. I can and do turn off the wanting machine. People are what they are and I can take them or leave them.
P.S. I also hear you state a belief that no one cares about you or ever has. I acknowledge that that is your experience and since you appear to only accept evidence to the contrary if it is in person, I invite you to visit Portland OR any time, or to meet me on one of my trips to New York this summer, or Bangkok. If you do meet me you will meet one person who does care a lot and doesn't want anything but to know you as you are.