For me it is more like, i should have started leaving a trace before the invention of modern genAI, now maybe is late. I could have had a trusted trace to prove that I am a genuine human, now I get the impression that faceless new accounts/profiles or whatever are all fake and automatically managed.

It's never too late; the important part is to have a personality and your own opinions. AI is agreeable, they will just go along with whatever information they are prompted with, unless they get an explicit prompt to be disagreeable. But you as a human have morals, values, experience and knowledge that you can apply to e.g. leaving comments or writing things.

But this was good advice years ago too. The average Facebook or Youtube comment section feels like it's full of empty drones, repeated and predictable comments that don't actually add much. HN comments are a breath of fresh air in that regard. Reddit can be to some degree, as long as you filter out the predictable kneejerk reactions and "I also choose this guy's dead wife" meme comments.