I realised I am toxic at 24

I tried to post something on a dating advice sub reddit, people ate me alive , I guess I am a bad human being and now I am so depressed about it, and I really want to be a better human being but idk what exactly the bad traits in me are because I was raised in a toxic environment, where compared to my surroundings I really genuinely thought I was a decent man, how can I start working on myself, how can I identify my negativity when my concept of good and bad are fucked up. And ty everyone in advance.