I really love my osprey ozone backpack. It has two side pockets that can each accommodate a 40oz hydroflask. The only drawback is it is 28l and that’s gets full quick. But I can fit my med kit and large lunchbox into the main pocket. If you need something bigger than that I really loved my Oakley Kitchen Sink for 8 years it carried everything I would need in a day and it still looks really good. I believe it’s a 36l or 38l.