You want certain products to list on your store and available for sale on some another store or marketplace. You want your product to redirect to another store on the click on the Buy Now button.
Also, you want to remove Add to Cart button from these products only.
If you want products to list on your store but sold at another store, you can do so by redirecting your products to another store. You can redirect to another store by clicking on the Buy Now button to buy the same product from another page.