It’s funny to hear they are not pack animals. I’m sure that is technically the case, especially in the wild, but my house cats definitely cling to me and follow me around like I am their leader. They groom/fight to try to establish a hierarchy below me, and when my partner comes home from work immediately switch allegiance to her, who they clearly see as the dominant mammal in the house.
They don’t go outside (they can’t really, it’s too busy by the road here and they’d decimate the wildlife, but I live with it because ultimately we’re doing them a huge favor by giving them a home, post-rescue) so I am sure that has something to do with it. Perhaps infantilism is keeping them in this pack headspace? But even then my mother’s cat — rural, murderous, tough tabby tom — treats her like a god and the rest of us as an annoyance.
I have 2 cats that are sisters. They have a very interesting dynamic. There isn't a fixed dominant sibling, they switch back and forth.
They antagonise each-other most of the time, but they also support each other in times of stress. If one goes to the vet and the other doesn't, the initial reaction is hissing and being a dick. Then, after a few minutes, it's licking and comforting.
I don't like to anthropomorphise too much, but they definitely look out for each-other. Equally, they definitely annoy each-other.
As I wrote, they're adaptable. But there's a difference between true pack animals with an established hierarchy and being solitary but being open to other cats and species. Certainly, some cats are more pack-like (lions) and others are, or are more open to, being largely solitary.