If you are wanting to sell to the same audience I would keep it in the same shop. If you have an established aesthetic that people like and a couple of hundred followers then those followers might also like some fonts that work well with your canva products.
if you plan on having a different aesthetic and are targeting a different audience for sure open a new shop. if you do clean canva templates and hand-drawn playful fonts the two are conflicting and will just make your shop look like it doesn’t have a clear voice. people will not know what to expect from your shop., and you will have trouble finding your niche audinece.
hope that helps. LMK if not and i can clarify hopefully