Not technically advanced. It was using a collection of 0-day exploits to get into a PC via a USB drive. Any basic hacker could accomplish that with existing exploit tooling.
What was so advanced about it was the coordination to enable it. The collection of 0-day exploits, the knowledge of the architecture of the centrifuge, and the engineering expertise to compromise the centrifuges in a non-obvious way.
Stuxnet was incredibly simple technologically, but it was distilled down to exactly what it needed to do and delivered to just the right people by an advanced vast intelligence apparatus. It did not depend on any breakthroughs in signals, encoding, hardware, etc. I'm not suggesting they aren't capable of technological breakthroughs, but stuxnet definitely isn't an example of one.