Recommendation for a ultralight backpack that I can also use daily when not hiking/traveling? (aka durability counts as well)

I just got pic related, but I'm worried that
1) without the sleeping mat, it's but a "bag" (rather than a backpack)
2) it won't last years

Basically I need something:

- 30-45L, ideally adjustable
- with an outside mesh on the back
- balance between lightwight (1) and durable (10) = 3,5