High fidelity prototypes, how complex and detailed they should be?

We are at the stage to test some of our high-end prototypes. Our client types are very different, from fashion to furniture retailers. So each client uses the tool in their way and also the list of the products and revenue we display are different per client.

I want to apply these constraints to my prototypes, using dummy data, I am updating every product, price, product image etc. As you can imagine, this is slowing the learning process as we can test fewer prototypes.

What are your takes on high fidelity prototypes? Do you think a different type of clients can align their mental model with other types of industries?