In fact, I see a considerable difference. Instagram and TikTok, have no meaningful social component. It's just content producers producing content for consumption by consumers. They are effectively cable TV providers, only deviating from traditional cable TV in that there is no hard limit on the number of channels.
HN is social media. Active, two way conversation which emulates going outside to talk to your neighbour, except with people around the globe, is what attracts people here. The users here aren't here just to watch TV like they are on Instagram and TikTok.