There is no minimum. The answer doesn't lie with how large your product catalogue is but your product differentiators. You can open a store with a single decor product for that matter.
Instead of looking at volume, think about these aspects:
- quality: is my product better? And how so?
- price: is it more competitive than similar products?
- innovation: does it have innovative features other don't?
- service: is my service better to influence the buying decision?

Hello
from my experience I would limit it to less is more, in that case I would suggest going with 5-10 skus at max. that way you have more control on what sells and you could always add more inventory as your business grows.