I think there are some features in all the main characters that I share. Lot's of those features are same ones that I like about them, and that makes it easier to recognize it in them.
Emil is maybe least like me. The most Relatable Emil thing is his hilarious clumsiness, but I like to think I'm less often prone to stupid mistakes than he is. I do try to think ahead and keep my head calm even when things get intense.
With Reynir (and Tuuri) I share their adventurous spirit and the desire to see foreign places. I like to think I'd be smarter than Reynir about my chosen method of travelling. I also get this sense of contentment when I help people, but I'm less likely to offer assistance if I'm not asked about it.
Tuuri is a manipulative little *krhm*. So am I. Like her, I really try to only use that particular trait when I can do good things with it. We are both book nerds, but we express it differently.
Lalli was my favourite character back when I first started reading SSSS. We share nocturnal lifestyle, love for forests, need for alone time, social anxiety, love for cookies, and a strong preference for people we know and like (or have a reason to trust). I make friends easier than him and can blend in easily enough if I want to, but I do have this internal me-people barrier thing going on. I think I was very much like him when I was younger. I'm still weird like him. Oh and I don't deal well with making mistakes.
Mikkel is someone I admire and I'd really like to hang out with him. His sense of humour is absolutely golden, and I could see myself doing same sort of jokes if I weren't concerned about embarrassing others. I like to plan things in advance and share his ability to draw conclusions from different clues (and we both trust ourselves to be right even when we really don't understand the situation due to missing information). We also both have a range of different practical and theoretical skills.
Sigrun is me in a party mode. I love being loud and boisterous like her, but rather than being my basic setting it's something that takes energy and requires periods of rest from me. She is courageous and really good at her trade, and that gives her the confidence in her abilities. Like me, she does best when she has a strong team around her to share the work and to fill in her blind spots. I have done my time in the military like her, even if the army in SSSS is very different than the one I learned my skills in.
Onni is my Top 1 disaster man. In him the social anxiety of Lalli is moderate enough to be on my level. He treats the outside world very much like I treat people who I know I'll never meet again, with stoic professionalism and polite distance. He shows affection in a very similar way I do, I think it makes him an easy character for me to understand. He has high standards for the people he considers important to him, and regularly demands much (too much) from them with their accomplishments. The highest standards he has set are the standards for himself. He is very loyal to people he cares about, but it's very hard for him to form deep and meaningful relationships where he can trust others implicitly. He is proud of his work but he is humble about it too. I have way less trauma to myself and exhibit these traits less radically. I'm also more adventurous and less afraid of everything new.