You don't need to make them waterproof. How long do you plan to drink a soda or whatever else?

My kids are done in max 10mins and they look mostly untouched.

I left it for one hour in a hot cocoa though, and it was not intact anymore but still usable to a degree.

Let's say somebody gets served their beverage when they sit down, then neglect it until after they're doing eating. In a cold beverage, I'd want a straw to last at least an hour. I don't think that should be hard to accomplish either.