High Sierra is a solid brand for backpacks. I have bought 2 backpacks from that brand, the first in 2014 (which finally gave in late december 2021), and the one I currently own which I bought in January 2022. As long as the laptop isn't too thick you can pretty easily fit it in the backpack I current own. Both of them fit my old MSI GT70 Dominator, which was a huge laptop, so your Legion 5 should easily fit.

This is the backpack I currently use, which is designed to accommodate 17" laptops.