It's good to have friends. They force you to compromise, they give you a perspective of yourself outside of yourself, opportunities to grow and develop happen naturally from spending time with them, and they give you unique opportunities to actively care about other conscious beings.
If we liken Family to Elementary School, Playmates to Middle School, and Friends to Highschool, than a partner would be College. You need to develop yourself with friends before you can hope to maintain a partner-relationship, getting a PhD is fucking easier than keeping a girlfriend. "What's the final stage", I hear no one asking? The stage you need to live with for the rest of your life, that there is no courses in, just you surviving and trying to make it until you die? The final stage is yourself.
Ultimately nothing outside of yourself can make you happy, but you need to find out what being happy is like first before you can know how to give that to yourself reliably. Friends are good at making you happy, at least good friends and not deadbeats. You gotta be careful who you associate with, champ. Friends are a useful reminder that you aren't as bad as you think you are, or as grandiose, they help you find the door to contentment, and once you learn to open it, you'll always possess the key, unless you gaslight yourself into thinking you're incomplete like a moron.
How do you get friends? Every friend I have close bonds with that go back years started out pretty much the same way: I reached out. I asked them about their passion, I sent them a DM, I showed them that I thought they were cool, because I did.
Making friends is scary and uncomfortable because you need to make yourself vulnerable and go out on a limb into uncharted territory. What's the worst that can happen, though, that they kill you? As the Baghavad Gita says: Fight and win, or die and enjoy heaven. You can't lose, so no reason not to give it your all.