Strategy and Concept

Strategy is how you want to execute your concept
Concept is what you want to emphasize or show about your product.

Strategy for Hydro Flask:
The brand likes to focus on unique and relaxing experiences, heating and cooling technology, and their durabilty. The feel of the brand is a boho calming vibe, so I think it best to use lifestyle advertising, slice of life, and maybe demonstrations, but steer clear of humor, as that does not seem to fit the brand.

In terms of concepts, I think focusing on a family on a camping trip sharing drinks around a fireplace would be a cute and unique way to show the relaxing atmosphere of the brand.
Another concept would be to show a group of people or a couple on a hike and they are cold, but the drink in their cup is very hot or vice versa with the people being very hot and their drink being cold.

The brand also loves to focus on nature so just showcasing someone on some kind of outdoor adventure using a bottle would be cool.