That’s the point; unless you’re saying that everyone with high karma is mentally unsound (which may or may not be a fair argument), being constantly online doesn’t seem to have much negative impact on most people.
But even for people like me I wouldn't say being online causes those problems, more likely some third factor makes them be super online and also shows up as other issues, though it may be a feedback loop (removing the option of being constantly online could do good for me)
Ironically, what helped me was to focus on Twitter. Specifically producing quality tweets. I was able to build an audience at my own pace, and it led to quite a lot of opportunities.
So in the same way one particular place isn’t always good to be, one solution is to spend time in a variety of spaces. I like irc/twitter/HN/tiktok, though I still lurk Reddit occasionally.
I haven't got WhatsApp, and the thought of it brings me out in hives. Would be difficult to step back from the web. SMS once had a huge draw, and that was an incredible time sink with less immediacy.
I don't know what that amount is.
What I can say is that each time I have successfully restricted my access to these places, it was followed by period of intense withdrawal, and after that was over, a notable amount of extra energy to do other things, to my very obvious benefit.
I'm skeptical that anyone has a non-addictive relationship with these places, and i was speculating that you are not an obvious non-example, despite your claims at having turned out fine.
I don't, for the record, think that the solution is as simple as denying your children access to social media while you still have control over them, but it also isn't obvious that letting them engage with it freely counts as a good form of innoculation.