I think it’s that neuro-diverse people tend to gravitate towards each other, so this is probably survivor’s bias. I definitely find that other people with ADHD are able to grab and hold my attention better than neuro-typical people and also they’re more understanding and forgiving when I’m flaky, or too hyperactive, or whatever.
I think upgrading the RAM as you mentioned is going to make a big difference. While the physical RAM might be soldered to the motherboard, you could buy a fairly cheap SD card or USB and set the system up to use that as virtual memory. It won’t be as fast as actual RAM but it might help and large SD cards are honestly really cheap these days.