I'm on the waiting list for a diagnosis, but it's extremely common for people with ASD and ADHD to experience this

I experience the exact same thing. It's very common for autistic people to have auditory processing disorders. I wear loop engage earplugs so that I can hear people better.

Sometimes your hearing or focus can be a little shakey, but that also sounds like it could be auditory processing disorder. I have it really bad and will sometimes struggle to understand what someone is saying, even if they're saying it clearly it sounds muffled and jumbled, and sometimes the processing actually goes through half way through having them repeat themselves

I think high sensitivity to sounds and being frequently distracted or overwhelmed by them is fairly often in individuals with Adhd/Asd and I also experience that quite often