This is the worst advice ever. Sorry bro. I usually hate the shit I promote. I hate dating sites, I hate the binary scams, I hate the fake weight loss pills, I hate... But these offers make me a shitload of money.Best niche would be the topic you love or crazy about. Then you will not need to do much research as you would be knowing many things about it on your own and also where you can find the proper information
The one thing that will make you hate the stuff you love is being forced to analyze them to death and tryin to figure out how to sell them to other people.
Keep the things you love to yourself and enjoy them. And push the stuff you know will sell anyway. This game is about money, not your emotional attachment to certain verticals.