To hide Add to Cart button and Quantity on Certain Products, you can follow these steps.
#1. First, create a tag with name:
natc
#2. Next, assign this tag for all products where you want to hide Add to Cart, Quantity
#3. Use this code to Website > Website Tools > Custom CSS.
/* Hide add to cart quantity */
.tag-natc div.sqs-add-to-cart-button-wrapper {
display: none !important;
}
/* hide quantity */
.tag-natc div.product-quantity-input {
display: none !important;
}