⚓︎the "rainbows and fluffy kittens" is some bullshit positive psychology that obliges people to distrust their own feelings and "put on a good face" even when they're feeling down; this makes them even more isolated because they make it impossible for anyone to truly connect them - so i wouldn't stress about that
as to what the point is: it depends on the scale you're thinking; it's the same with anything that's alive; a tree in a forest is in a huge network of beings, and on a planetary scale can do very little on its own; but then to its immediate surroundings it makes a huge difference - throwing shade, providing space for moss to grow and birds to nest, etc.
also, there's the butterfly effect - you might say something to someone, which will make them change their mind about some decision, and that might impact a further 10 people, etc.; this happens all the time; the system wants us thinking that our decisions don't matter, because that way we're easier to control; this is not true; everything you do matters; what you do matters to me as a fellow human
cynicism is safer than idealism; to believe that what you do matters is risky, and is also what we all need; we all need you; there is some stuff that nobody can do but you; again, you matter; i'm sending you hugs