I’ve used this one on my last few trips. I find it more comfortable than a drawstring bag (straps don’t dig in), but it’s still the convenience or the size of a drawstring bag. It also has the things on the side to slide water bottles in for easy grab access. it also folds up into itself!

https://www.amazon.com/dp/B01DNGEN6E/ref=cm_sw_r_cp_api_i_JHpVCbRBG9E6K