Shopify or WooCommerce, depending on what the catalogue and the accountant prefer. Stripe at the checkout. Real product pages, real inventory, real receipts.
Most stores we are asked to fix were built in a weekend by someone who left town. The product pages render, the cart adds items, and then the checkout fails on a card the owner has been swiping at the register all year. We rebuild from the checkout outward. The payment flow is tested with real cards, in real currencies, against real tax rules, before the homepage is touched. Once money can move through the site without supervision, the rest is layout.
We pick the platform to fit the catalogue, not the other way around. A shop with forty SKUs and one warehouse runs on Shopify and stays out of trouble. A shop with custom fulfilment, subscriptions, or a content side that pays its own way usually wants WooCommerce on a host we trust. Either way, the code stays in your repository and the credentials stay in your password manager.2
Before launch we run the site under load that exceeds your last good month by a factor of three. A store that quietly times out on Black Friday is a store that has been built once and tested zero times. We would rather find the bottleneck on a Tuesday in April.