I went down a rabbit hole with this a few years ago because of how strongly I resonated with diagnosed friends' listed symptoms. She sent me a checklist from her own assessment. I read the list out to husband, who nodded at every one especially his bugbear, which is that I never put things in the right place. After 30 years together, though, he does now know if he can't find the marmite in the cupboard, it's in the fridge...
Anyway, further research revealed that the traits I do have can be attributed to the Dyscalculia diagnosis I already have - there's a lot of comorbidities between dyslexia/Dyscalculia and ADHD.
After that, I gave up, because honestly I found I wasn't doing myself any favours with all this navel-gazing. I am 52, I have survived this far, my life isn't severely impaired. If anything, the Dyscalculia has been more of an issue because my numeracy is so poor, it's affected my employment choices. It might help me understand why I struggling so much with the (apparently 'basic' according to a lot of MN) skill of driving that I have never learned, but honestly, I still ain't gonna be driving, so it doesn't really matter why I couldn't get to grips with it.
Put it this way, as far as I am concerned, I don't have anything that impacts my daily life enough to warrant another diagnosis. I have met people who do, and it's been a massive benefit to them. I am not at their level.