Ask HN: Modern self-hosted e-commerce solutions?

The recent discussion about FedEx starting a marketplace to compete with Amazon reminded me that, once upon a time, people would host their own e-commerce sites. While not as popular as they once were, I imagine e-commerce solutions have a come a long way since I lasted checked in on them a decade ago.

If you wanted to self-host a small mercantile business, what options exist that could produce a good customer experience?