Neverending trouble with friend groups

You're not doing anything wrong. It's the "double empathy problem" which in a nutshell is anytime people have vastly differing experiences they struggle to empathise with each other. Since autistic people are in the minority we get marginalised.

https://www.autism.org.uk/advice-and-guidance/professional-practice/double-empathy

This is why I dislike pathologising a neuro type - the default is presumed to be neurotypical and anything that isn't neurotypical is judged as deficient, wrong and disordered. Our way of being in relationships is different than the majority of people and is misunderstood by them, for example I show I trust and want to be intimate with someone by sharing my special interests with them. NTs see this as "going on" about something and it bores them. So I have learned over the years that I mustn't do that if I want to keep a friend, which means I can't be authentic in relationships (masking) and it becomes really hard work for me. I'm actually a really good friend, I'm supportive, I'm there for people when they need help, I listen but this is rarely reciprocated. Last year I realised that there is a pattern of people telling me secrets that they don't tell people they feel close to because they know I'm non-judgemental, trustworthy and empathetic. Basically they use me as free therapy for stuff they feel ashamed of or don't want their friends to know because they think it will make them look bad. When people used to do that I thought it was a sign of friendship between us but then I noticed I was getting excluded from things and I was only being contacted when they wanted something from me. 

I think the solution is to have autistic friends but that has it's own issues. I don't have answers, just acknowledging that you're not alone and it's not you it's the combination of NT and autistic. 

You're not doing anything wrong. It's the "double empathy problem" which in a nutshell is anytime people have vastly differing experiences they struggle to empathise with each other. Since autistic people are in the minority we get marginalised.

https://www.autism.org.uk/advice-and-guidance/professional-practice/double-empathy

This is why I dislike pathologising a neuro type - the default is presumed to be neurotypical and anything that isn't neurotypical is judged as deficient, wrong and disordered. Our way of being in relationships is different than the majority of people and is misunderstood by them, for example I show I trust and want to be intimate with someone by sharing my special interests with them. NTs see this as "going on" about something and it bores them. So I have learned over the years that I mustn't do that if I want to keep a friend, which means I can't be authentic in relationships (masking) and it becomes really hard work for me. I'm actually a really good friend, I'm supportive, I'm there for people when they need help, I listen but this is rarely reciprocated. Last year I realised that there is a pattern of people telling me secrets that they don't tell people they feel close to because they know I'm non-judgemental, trustworthy and empathetic. Basically they use me as free therapy for stuff they feel ashamed of or don't want their friends to know because they think it will make them look bad. When people used to do that I thought it was a sign of friendship between us but then I noticed I was getting excluded from things and I was only being contacted when they wanted something from me. 

I think the solution is to have autistic friends but that has it's own issues. I don't have answers, just acknowledging that you're not alone and it's not you it's the combination of NT and autistic.