Backpack for my boots

So I travel to my local rink mainly by walking or riding my bike and I’m realizing how uncomfortable my backpack is because it’s too small for my boots.I don’t want a duffle bag or a rolling pack, I was looking on Amazon and found some made for skates but I’ve seen them in person and they look like they’re suppose to be kid sized. I think my skates would fit but I don’t know if the bag would fit on me.What bags do you use? What dimensions should I be looking for? I’d be super happy with just a bigger backpack but idk the size of my current one!