I can relate in some ways.
I have a really great friendship circle of about 6-7 really close friends but we are in very similar in that we all like our own space and have no need to be in each others pockets,
don't like loud nights out or drama etc and I'd say all of us are really happy in our own company. It's taken a long time to get here and develop these relationships...we started slowly and built from there over years.
Prior to that I had "friends" in my late teens and twenties but I didn't really like them or enjoy our times together..."the girls". I knew I was meant to have a friendship circle and go on nights out as it was the social expectation. But I'd usually dread our times together, get anxious before we met up and frequently cried in bed after meeting up as the circle was "bitchy", toxic really and I didn't how
to play the social game that was going on. In the end I was "lovingly mocked" and laughed at one too many times and I ghosted the lot of them.
For a year, I had NO friends. I went to hobbies, the cinema, concerts etc on my own. I loved it. God, there was so much PEACE. I could just be me! It was great.
A few times, I'd meet people and they'd be eager to be friends and I'd feel panicky and anxious again. Then an older woman said to me, "You don't need to be friends with everyone, you know? You don't owe anyone friendship. You can be polite, but say thanks but no thanks if you don't gel. It's life and they'll get over it."
It was quite life-changing, really. Up until then I think I felt like I had no choice but to be friends with whoever latched on to me as I had to "Be Kind". Then I'd feel suffocated and trapped and unhappy.
My own history is that there is some attachment trauma from a difficult childhood, some bullying and exclusionary behaviour in junior school and...an AuDHD diagnosis. I'd say most of my friendship circle are high achievers with AuDHD too, and some exes! Our default seems to be that we appear confident and popular but don't really like most social situations (the phrase "I hate people" gets bandied about a lot when we meet up!) we all need a lot of downtime and we all get on because we can unmask around each other and bond for who we really are. Then leave when it all gets too much!
I don't know how or why, I suspect it's because I am comfortable in my own skin and don't need anyone, but I make friends really easily. Too easily and I don't like it. Like you, it seems I can't go to hobbies or days out without someone asking if we can swap numbers and I feel too uncomfortable to be impolite and say, "No. I'm not really looking for more friends, thanks!"
I'm having to stop going to Zumba because a woman there has just decided I am her best friend. She brought me a plant on my 3rd week there "just because", presented it in front of the whole class and then asked if we could have a cup of coffee immediately after the class. I had a routine of blissfully sitting there with a book and coffee every week enjoying a rare moment of alone time. I loved it.
But I felt obliged, and the next thing I knew I had her whole life story, an invite to have dinner with her and her husband and there was an expectation of at least weekly coffees and catch ups and loads of other social activities, wanting to "pop round" or have me "pop over" to hers so we can have a "good catch up and therapy session!" (I've avoided giving my address!) and annoying, "hello my amazing friend 😊😊😊 what are you up to today?" texts. And "saving a spot for my bestie" every week at Zumba. I've only actually met her around 6 times in total!
She keeps referring to us as we all the time..."Are you coming to Zumba Hunni? xxx 😘😘😘" "No not today, I've broke my arm." "Oh no! I've got a cold! What are we like eh? No worries, fancy a coffee and cake anyway? We love a good cake don't we?! 🎂🍰🧁❤️❤️❤️"
I keep seeing on MN that ghosting is cowardly and only terrible people do it and we need to #bekind to everyone and we never know how lonely people are and it's "MEAN GIRL!" "you sound like a bitch!" vibes if you don't want to be friends with everyone.
I don't want to ghost this woman and do feel sorry for her but I don't actually like her, feel like it's all too cloying and I just want her to leave me alone and get the hell out of my life. I know she will be extremely hurt if I say, "sorry, I don't really want to meet up or socialise. I think we're too different and I really like my alone time and don't have enough of it." She's a real social butterfly and really needs to have people around her all the time, but I don't and she doesn't get that at all.
For now I keep making excuses and doing Youtube Zumba! I loved the class and instructor but it's not worth the loss of peace.
Anyway...this is all just to say you aren't all that weird...I'm weirder obviously haha! There are other people who feel like you, you aren't alone. Feeling happy in your own company is such a gift, embrace it.
It could be neurodiversity. It could be trauma. Or an ambivalent/avoidant attachment. Or you could just be an introvert who is happy in there skin. Whatever it is, there is nothing wrong with you. Just do what makes you happy and don't spend your free time making yourself miserable to make other people happy. You're fine as you are.