Decent capacity, sweat proof commuting backpack?

Hi everyone! I'm hoping you can help me find the right backpack because I've gone down the rabbit hole and there are just too many options.

​

I commute about an hour each way through Madrid using buses and the metro. It's often very crowded, so I'm standing for much of the commute, and I also have several fast walks between stops. Madrid gets extremely hot in the summer, and I sweat pretty easily, so comfort and breathability are huge priorities.

​

Here's what I typically carry:

- 15–16" laptop (so it needs a well-padded laptop compartment)

- Charger and mouse

- Notebook(s) and pencil pouch

- Water bottle

- Coffee thermos

- A few pouches (medications, first aid, makeup, deodorant, etc.)

- snacks (I have a lunchbox but if I can fit food/snacks in the backpack that's a huge plus)

- Occasionally a light grocery shop on my way home, so I'd like some extra capacity.

​

What I'm looking for:

- Comfortable for a long daily commute

- A back panel that minimizes sweating as much as possible

- Good shoulder straps that won't dig into my armpits and weight distribution

- Water-resistant (or at least able to handle light rain)

- Around 24–30L, but I'm open to suggestions

- Professional enough to take into an office (it doesn't have to look like a hiking backpack, but function is more important than style)

-External pocket(s)

- Budget: ideally not above 100 eur.

​

Thanks in advance!