Genuine question: How does one acquire mutuals? I've been in fandom spaces for around 4 years now since I mostly avoided social media before that, and I'm so viscerally cooked at trying to talk to people in those fandoms, so do you have any like tips on approaching people and stuff or am I just too introverted for that to work?
The good thing about Tumblr is the fact that within the fandom space, we're all here for the same reason -- to be real deranged about our blorbos. Unlike real life, you don't have to shoot in the dark for small talk topics, you can just find a post tagged with Your Character and comment. And chances are, OP will want to talk about it!
I'm an introvert's worst nightmare online, cause I will DM anyone. I just want to talk. But I've actually had a huge success rate from it (and got a wife from it too lmfao) so sometimes being bold works. Also the worst anyone's ever done to me from doing that is not reply, so it's really not a big deal.
You'll have to leave your comfort zone, unfortunately, but look for spaces where people are already talking or sharing content and just chime in. Someone talking about a cool piece of fanart? Comment and say "omg I love that one too! Have you also seen xyz?" Someone posting a fic snippet? Comment and say "omg I love this! Do you think in this universe they'll xyz?"
You HAVE to use open ended questions or else the conversation will die and you won't get the opportunity to learn enough about someone to become friends. You can't just say "wow amazing!" on a piece of art and expect to be instant best friends. OP will reply "thank you!" and that's the only interaction you'll get.
You also need to be repetitive. Much like with making friends irl, you need consistency with your attempts. I go walking most mornings and because of that, I often see the same few people and we now say hello or stop to chat about wildlife in the area. Show up in the same tags or comment often on posts, and people will start to recognize your username and be more open to chatting.
Also, I know you said you didn't do socmed before, so I'm not sure how much you do now, but a really easy way to get new fandom friends is via Discord communities. I don't know what fandom you're in, but if you dig around, someone will usually have a Discord. Join, chat, and then when you find people you super vibe with, you can start to DM. From a fandom perspective, Discord sucks because it's so separate and locks conversations behind doors, BUT it's great for making friends.
The thing to remember is that you're allowed to be in these spaces. You're allowed to take up space and try to talk to people. That's what fandom is all about. Not every conversation will lead to new friends, but you need to be okay with trying again and again. Just see what happens!