We used these and used a carabiner to connect our water bottles to the outside of our bag. Bottles take up lots of valued space in bags.

https://www.amazon.com/Windspeed-Carrier-Outdoor-Handheld-Jogging/dp/B01LZ3S9ST/ref=mp_s_a_1_4?crid=38WXPQ6A0YSCU&keywords=bottle+band&qid=1687389761&sr=8-4