As an ADHDer (and highly talkative person), I've almost always been vastly overexperienced for the role I'm in. I'm late diagnosed and only recently treated, but the meds/therapy have shown me that I'm not defective; the system is, which has helped me to move forward.
I was afraid to apply for a promotion because of what I now understand is Rejection Sensitivity Dysphoria, common to both autism and ADHD. We have typically received 20,000 more negative messages than a neurotypical person by the age of 12, leading to intense anxiety around situations where we might be rejected, such as job interviews.
(Tip: I found the book '101 Interview Questions You Need Never Fear Again' by James Reed to be very helpful - having well-rehearsed answers to standard interview questions, so you don't have to think in the moment. There are dozens of YouTube videos to coach you past a whiteboard test, too.)
I've learned to tell the recruiter that I'm feeling nervous - one even phoned me after work, in his own time, to tell me about the offer so I wouldn't be pacing the floor all weekend.
I've learned to talk to HR. One set me up with "soft skills" training courses on persuasion, negotiation and presentation skills and offered to run practice interviews with me. Another is setting up group workshops for neurodivergent colleagues to coach us through specific challenges such as low self-confidence.
Yes, the system is unfair and it sucks, and we are often held to higher standards for internal promotions than any external candidate would face - which is awful when you've found a company that accepts you exactly as you are.
Talking about it honestly, sharing your needs and asking for help is a good starting place to make the system fairer, even if it won't solve it overnight.