Beste rugzakken voor de basisschool

In your experience as a parent or kid in Leuven, what is the most durable and sturdy backpack for a primary school child?

I am asking specifically about Leuven because children here often cycle and need to carry lunch, fruit, A4 folders, and sports gear. I would like something that can handle daily use, rain, and bike transport without falling apart.

At the same time, I would prefer a model that does not make a child stand out too much and blends well with what most children here use.

My priority really is long term durability. Any recommendations based on real experience?