Books about strong platonic friendships? Preferably sci-fi/fantasy/thriller

DISCLAIMER: Triggers cuz mentions of abandonment, friendship, divorce, etc

Okay so I’m kinda going through a weird season – my relationship with my brother(who has basically been my best friend for years) is falling apart ever since he got a girlfriend, and my parents have a divorce— yes I have therapy, no I‘m not trying to ”fix” anything, it’s as good as gone and that’s okay – but I do want to read something that explores what I’m struggling with. Like, what IS friendship? Why does it matter? What’s the point of having friends when you have a romantic partner? Can a person be single and still be happy?

I strongly believe that fiction can help people confront and see deeper into issues they deal with, so this is the first time I’m seeking that out for myself.

Preferences:

1. Any genre, but I prefer fantasy/sci-fi, then thriller/horror. Don‘t hold back recs cuz it’s in a different genre. I just have a strong preference.
2. Absolutely no romance, please – It’s a new change for me, but I’m not in the headspace for it.
3. I don’t mind female friendships, but as a guy I’d prefer male friendships, though it’s not a requirement.
4. I want them to be well written and fun! Not looking for traumaporn anything like that—just something that deals with these topica

And just to clarify, I’m not jealous of my brother’s relationship. I’m happy for him. It’s just that when everything began to revolve around that relationship, I became a third wheel constantly when I needed support(I have some bad health so to speak) or tried to support him. When I had it brought up, he got defensive and kept growing distance – so it faded. I’ve still accepting it, but I’m looking for stories that explore strong, fun platonic bonds.

Thanks so much for any recommendations!