Take a look at the 1Password model. No free layers. It's about piece of mind. All upsell-based models require marketing that centers on suggesting to base users that they are not doing enough. There is just no way around it. And that drives anxiety and makes them hate the free layer of your product, regardless of how good it is.
On the 1Password, I pay the base layer and I know I am as valuable as a customer as the other stuff they sell. They never offered more stuff to me because they don't need to and they do not want me thinking that I am not doing enough to secure my keys, even at the base layer. It makes a huge difference.