YC itself is opaque. All their rejection emails are a simple "sorry, we can't tell you". I don't know if they are afraid of legal liabilities or the reasons are much more mundane : "It's been 2 years and your revenue is only $2k", "AI is overhyped", "Too small a market", "You look dodgy" etc.
>Don't raise money unless you want it and it wants you.
I wish I knew this before I went on a wild goose chase for angels.
The only two startup articles I read are either PG or indiehackers and I am impressed with how clear and lucid this dude is with his words.