I have a Maxpedition Sitka that fits the bill, but riding a motorcycle I feel it would be better to have to straps. Any bag that can hold a light to the Sitka, but has two straps? It does not have to be tactical. Having a Nalgene on the outside that does not take interior space is probably a plus in my book, but do not hesitate to recommend this as I am no expert. I carry a few tools and added an organization pouch to the bottom section for work in the Sitka
VanQuest is having a "fire sale" on the Trident 20 right now. Could add any number of bottle holders, H2O carriers, or like pouches to that pack. Could also mod your Sitka with two pack straps.
MAP 3500. Duel h2o pockets and nearby compression straps you gan thread through the caps loop to secure the bottles while riding. Decent organization, though not tons of it. A little bigger, overall than a Sitka. No PALS, so it is decidedly untactical, but is still available in tactical colors, including multicam or scorpion or whatever we call it these days. I like it so much, I own three (my sons and I use them for day hiking).
I've chosen this bag over a TAD EDC, Maxped Xanthar, and a plethora of others. I still have the mentioned bags and they just could not do what this one could for the size, weight and organization.