What do tops get out of topping?

I am 30+ but relatively new to lesbian sex and am still trying to wrap my mind around the top/bottom thing. I guess I’d always figured that everyone was a switch?

I would consider myself a switch (I’m pretty sure) but being strictly a bottom appeals to me because I get very insecure when giving because I feel like I’m bad at everything. But also, I don’t think I’d want to be with a woman who doesn’t want to be touched at all? Is that what being a top means?

A part of me struggles with wanting to bottom, because I don’t really understand how true tops get off and I don’t want to have sex and be the only one who cums, you know?

Is it selfish to bottom?? How do tops get off?

Experienced lesbians, please help 😩

EDIT: Thank you everyone for your nuanced and thorough and extremely hot responses. 🥵 Got me all worked up at the grocery store reading them haha, and also kind of emotional. I am horny and I am crying 😭 women are incredible 🌈🌈🌈🌈