I went full vintage and bought a leather backpack. It's been incredibly durable so far, has a great look, and stands out a lot. It may be more than you're looking to spend, but there are others that are cheaper. Note, though, you need to be careful as if it's not full leather, it may come apart easily.

https://www.amazon.com/gp/product/B07D3NY2YF/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1