Hi :) For reference, I'm a diagnosed, "high-functioning" autistic woman from the UK. I was diagnosed at the age of 12 despite not being 'obviously' autistic at all, and I completely understand how rare that is, as I have seen many autistic people go through hell and back trying to get a diagnosis of some kind. There is absolutely a problem in ignoring autistic traits in women + non-cis people, and most people here would not deny that.
In all honesty though, I do not support self diagnosis. I believe you have every right to acknowledge the traits you may have, and you should definitely not feel like a fraud for making the correlation between those traits and potential ASD - as you said, many people slip through the cracks in the diagnosis process. However, I disagree with definitively labelling yourself as being autistic, and I know many other autistic people feel the same. Personally, I do think there is a difference between having a professional diagnosis and being self-diagnosed. Firstly, at the end of the day you simply do not have the training to diagnose autism. As flawed as the system is, there is a reason why only very well-trained people can diagnose autism, and that is because it is an incredibly complex disorder that has traits which overlap with many others (ADHD, OCD etc).
Secondly, there is the fact that having a professional diagnosis makes your life (in many cases) significantly more difficult than someone who is self-diagnosed. This is why you may face a negative reaction from autistic people, alongside the connotations of self-diagnosis with the people who want to be 'quirky' (not in reference to you at all, but it's a big reason why people dislike self-diagnosis). We are, the vast majority of the time, the ones who face the discrimination, with an 86% unemployment rate where I live. We are, in many cases, forced to declare our diagnosis if we stand a chance of getting reasonable adjustments made in the workplace / education, and that consistently puts us at a severe disadvantage in terms of gaining employment. I am applying to University this year, and I have been told many times that I should hide my diagnosis because it will hinder my chances - for context, that's in reference to some of the most liberal Universities in my country. I am still at a disadvantage. There are a multitude of other issues, including police brutality, receiving proper healthcare, mental health assistance, education and legal discrimination etc. Basically, and I really hope this doesn't come across as rude because I don't mean it to be, but there is a big difference between saying you might be autistic and being diagnosed as autistic, primarily in the ramifications that come from it.
Again, you are not a fraud for making the correlation between behaviours and autism, and there's nothing wrong with saying you think you might be autistic, and engaging in autism communities etc etc. Please please do not feel guilty for thinking you could be autistic. The problem comes when you say you /are/ autistic if you're self-diagnosed. Autism is a disability, and a very complex one at that. Whilst I think you can (to an extent) self diagnose mental illnesses / disorders such as anxiety, sensory processing issues etc which are often identified alongside autism, I don't believe you can diagnose yourself definitively with ASD.