Carrots and parsnips are pretty soft in hard-veggie land. Shigefusa gyuto is the best I have used on those. Butternut squash, I really like my Martell 300mm suji. Best I have used. Other super hard squash (delicata, etc), hard sweet potatoes, rutabaga, things of that nature; a well ground non-laser gyuto is usually my go to. Like mentioned, technique matters, a lot. Try different cutting motions and product orientation. The same knife can be awful with one cutting motion and spectacular with another. And yes I know some of these aren't root veggies, but they are hard and the cutting techniques are similar.