I feel genuinely stupid? AuDHD has ruined my brain

Like the title says, AuDHD has ruined my brain. I retain no information, I can’t do anything.

I don’t feel autistic enough, because I don’t have any special interests, because I can’t focus on anything - I can’t read, I can’t watch tv, or films because I just don’t have the attention span.

Was trying to explain that as much as I’d like to pick up a hobby like knitting or crochet, I know it won’t go well because 1) I’ve never found a version of giving instructions that actually works for my brain, every single type of giving instructions I engage with feels like it’s just hitting my forehead and going nowhere else, 2) I get frustrated and overwhelmed when I don’t understand the instructions and 3) I’m very much one of those people where if I’m not automatically good at something, it kills off any desire I have to actually try it.

I feel genuinely stupid, I’m in uni doing a postgrad degree but I have no idea how I’m here. I don’t understand the content, I have nothing useful to add to discussion, and it’s quite clear I’m out of my depth. I don’t understand how people can just.. do things, it honestly feels like I’m just pretending constantly, and everytime I try and explain that hey, actually, I’m incredibly incredibly stupid, no one takes me seriously and I really wish they would.