Most people find notifications very useful - enough people in fact that Growl being a third party app you have to install in order to get notifications was extremely popular and lasted for 17 years.
Some applications do seem to think they are more valuable to you than they actually are, but that's usually going to be product managers with an inflated sense of their own importance rather than trying to attack you.
You say you have ADHD. I also have ADHD and I can tell you that NTs generally aren't malicious or sociopaths or intentionally trying to destroy our focus - they're just ignorant and building for what they know in the same way sighted developers tend to produce websites blind users can't access.
You don’t need to allow notifications from random apps to make them work for you:
your-long-running-script && osascript -e 'display notification "Done"' || osascript -e 'display notification "There was an error!"'The issue today is that every application now offers notifications, and only some of them are useful. So disable the ones you don't need.
Not once on 20 years of computing did I ever think: “I want applications to interrupt what I’m doing and steal my limited ADHD focus because they’re lonely and need attention”.