I had this same debate with myself earlier this year, after speaking with several therapists and a doctor that specializes in autism diagnoses, I decided the time and money to get diagnosed was not worth it.
For me, I considered how I was struggling and whether a therapist could help. I struggle with overstimulation, but a therapist can't do much for that; I addressed it by getting noise cancelling headphones and wearing sunglasses inside. I struggle with burnout, but a therapist can't do much for that; I had a frank discussion with my boss and we agreed to reduce my work hours and I started saying "no" to social events that would be too draining. I stim and hyperfocus but I don't find those problematic. I'm extremely lucky that although I have poor social skills and no friends, I am not lonely and don't feel like I need to make any adjustments to my personality to make friends, this might be one area where a therapist could help.
My point is that, autism is something where you can't treat it overall, you can only treat the "symptoms", so narrow down what is causing you stress and look for solutions. If an autism diagnosis requires meeting a threshold for 6 issues, but you only have 5, that doesn't mean you can't get help for those 5 things. A therapist may be able to help with that and if you want them to see you as autistic, just say you're autistic. I doubt they'll ask for any proof and if they push it just say you were a kid when you got diagnosed and you don't have any paperwork. I'll say that in my experience, the most important aspect of therapy is getting the right modality and this can be tough. It can be difficult to find providers that don't just do CBT and sometimes they aren't very good about discussing what you really need they'll just do whatever they are trained to do. I found it really helpful to go to Psychology Today's website and see all the different modalities that existed, then researching what each of them were and thinking about which may be best for me.
Try not to get hung up on the idea of getting that diagnosis. There's a school of thought that diagnoses are a capitalist construct that aids a doctor in getting paid by giving them a billing code to submit to your insurance company.
Stardew Valley and Core Keeper ;)