On hardware level, all those use von Neumann architecture. Wasm, however, exposes Harvard architecture (implemented on top on von Neumann machines). Yet, you can compile C to Wasm, which is a data point about how abstract C is: so abstract that it can target Harvard architecture despite targeting just von Neumann architecture being sufficient for targeting modern hardware.
are there ? how many laptops, desktops, smartphones, tablets, use anything else than the von neumann architecture ?