[p00dles]

Sir/madam, have you ever tried an Osprey that suspends the weight of the bag off of your back with a sturdy piece of mesh and very minimal metal internal frame?[1] (I think Osprey pioneered this, other manufacturers now have it too). It has been life changing for me. I use it daily for commuting, and just finished 3-week tour through 3 countries with laptop, Kindle, and everything else packed inside this one bag. I’m sure Osprey has smaller versions if 34L is too much.

[1] https://www.osprey.com/us/en/product/tropos-TROPOSF19.html

[gs17]

The metal frame must be the key. I have an Osprey backpack without it, and the mesh alone does almost nothing to help with sweat, even though it was sold to me as being better. A friend in high school found an old Vietnam-era? US army rucksack with a metal frame that was less comfortable in the short term but not bad in the long, sweaty term.