Do you need your own listing on Amazon to be succesful?

Since you all are the Amazon experts I would really appreciate some of your insight on this…

Some more background info:

I recently bought a business that used to sell their product on Amazon so a listing already exists for it.

I have been granted access by their Amazon account to sell on their listing and I have registered the product’s trademark in brand registry as well…

Would it benefit me to create a new listing separate from their original listing or should I continue to sell my (formerly their) product on the old listing?