Do you recommend selling more than one niche?

I’ll be registering my private label in a couple of days, but in Europe you gotta decide a class for what you want to sell. My first intention was to sell pet products like cat scratching boards, dog collars etc.

My first product is gonna be pet hair brush which is gonna be in class n21 (if I’m not wrong), where there are other things like sponges or cleaning utensils.

I thought: “if I’m already registered for selling those things, why not?” Do you recommend selling also those products? Or will it just ruin my label?

(Additionally cat scratching boards are in class n28 together with sport products… I will register to that class too, but don’t know if selling running shoes with pet supplies is even a good choice)