To get a relationship, all you need is something to draw in a prospective partner, as long as you are not physically deformed or completely hideous. It could be a hobby, an interest, physical attractiveness, or really anything. But there has to be something. Then you need to talk with someone once and use that thing to make enough of an impression that the person wants to talk with you again. In those years at home, did you develop any such ways to connect with people?
If so, then you just need to go try and talk with some people! It might not work out the first 8 times, but if you try enough, then you are certain to find someone eventually. It's really not that big of a deal to get rejected a few times - that's why we have phrases like "shooting my shot".
If not, then there is some merit to the arguments that you should "fix yourself" before pursuing a relationship. I'd still say go for it, but understand that it's going to be a low-percentage play while you lack the tools for success. You might get more bang for your buck if you instead developed some passion or hobby, or at least found something you could pretend to be passionate about.
On the topic of being authentic, there is absolutely nothing wrong with being skeptical about life. You just need to understand that some potential partners will be thrown off by this. Sometimes, it could be to your advantage to downplay it initially, and then only start talking about it once you're far into the relationship. By then, you and your partner will be more comfortable around each other, and your partner will likely be more open to hearing your true thoughts.
Are relationships fun? Absolutely. Will they make you a better person? Quite possibly. But will they resolve your years-long skepticism of the merits of continuing to live? Probably not.
I've been in several relationships. They were great. And now I'm here.
Best of luck!
