How is that? Does risc-v have magical properties that make its designers infallible, or somehow make it possible to fix flaws in the physical design after the CPU has already been fabbed and sold?

Because that’s physically impossible for tons of people. CGNATs are very common.

Well nothing is impossible, but it does complicate things very much. Certainly outside “just run a container and call it a day” territory.

That’s… a rather huge drawback. Why even pay for a shield at that point?

? How would that even work? Does openwrt have a feature where it can hack into the ISP’s infrastructure and modify their QoS settings?

DDNS won’t save you from your ISP sticking your modem behind a cgnat and blocking critical ports. Which is not an uncommon scenario at all.

There are ways around it, but it’s still not very straightforward. Also often with some significant limitations.