I’m pretty fond of my Deuter Speed Lite 20 as a day pack. Comfy, lightish by our standards, side waterbottle holders, smaller top pocket for quick things and has a removable webbing hipbelt.
Issues - Front stretchy stash pockets are amazing, and can’t say I like the one on the Deuter, For some reason has a stupid sewn top over just a buckle. Would have also liked daisy chains on the shoulder straps to attach a cellphone pocket. Only other problem would be Deuter uses propriety sized clips and grosgrain for no apparent reason, which means they can’t be replaced off the shelf.
With some more perspective on it now, wold probably give the Osprey Daylite a better look. Or the Talon 22 if I was into more technical stuff than I am. But at that point things are getting pricey for a day pack.
Major thing for me was figuring out that about 20L was the sweet spot. Smaller and you are hauling jackets out to find snacks, and often loose the stash pocket in the designs for some reason. Larger and you are likely to bring more stuff for no real reason