Idk if it falls into this category but i’m confused with ADHD

I keep getting told that ADHD is this ‘fake’ and ‘made up’ to excuse someone’s behaviour and I for some reason have been getting grief for it 🤣. I have autism too which is also probably ‘made up’, but i thought that adhd affects your frontal lobe in your brain, affecting impulse control, inhibition and all that. But of course according to people believing the Earth is flat that can’t be ‘real’. Why are people calling me fake can someone please clarify it 😂🤣😭