Adult assessment query

I’m looking at various online providers to self fund a private assessment to better understand myself and how to rebuild my life.

Is there any reason why I SHOULD choose a provider who is using ADOS or who does not? I don’t really understand all of it despite my best efforts. I just know it needs to be NICE gullies? ICD 11 and DSM 5?

I was diagnosed with ADHD 2.5 years ago with the nhs and have been on the waiting list for ASD ever since.

I’m in my 30s if that’s any use/ I don’t really mind if the nhs accept it or not given the nhs isn’t anything to do with making accommodations, social skills, education or employment.

Thankyou for any information or advice you may have 😊