Depends on how much customization if you just want off shelf solution, if all the features are relatively standard, you can use one of the off the shelf ecommence platforms like BigCommerce or VTEX.
You can also try out WooCommerce if you or your clients are familiar with Wordpress.
Of all the off the shelf solutions, Magento is probably most customizable, and it is open source. But to get enterprise edition can be really expensive, so check if your client is ok with it.