All modern phones run the risk of breaking when you drop them, they’re made of glass, gravity doesn't respect glass. I’ve never broken any phone because I don’t go around dropping them.
Samsung, Google, Apple, they’re all as tough, or fragile, as each other. As for the heating up thing, I don’t have the 15 so I can’t judge that. I did have a Samsung Note 7 that got recalled because it was literally exploding.