Mira

I literally just bought the Osprey Mira 24 and took it on a hike yesterday and it’s so great! I only buy packs with air gap backs because I sweat a ton and it helps reduce chafe, but I had 3.5L of water in it (it comes with a 2.5L bladder), a few layers, snacks, and barely noticed it.

I'd really recommend the osprey just because they do great packs, we use slightly larger Mira (female) and manta (male) packs think they're about 34L. The osprey packs are really well designed, lightweight and comfortable. Only issue is sometimes the zips get a bit sticky. Buy one 2nd hand on market

I would suggest a backpack with a water bladder. I stayed noticeably more hydrated than with a water bottle and getting headaches and tired. I started using the water bladder and tube attached via a magnet near my mouth. I was consistently taking small sips and felt much better. Don’t know if you ha