Opinion pieces on the Internet and political saber rattling by low level politicians does not a nuclear policy make.

States actually have quite a few different ways of signaling they are serious about potentially ending the world as we know it, and Russia is currently using none of them.

As an example, the Russian state’s own published nuclear policy has remained unchanged for over a decade and still explicitly prohibits nuclear first use in cases like this. Currently high level Russian politicians including Putin continue to reference said defense policy in response to questions about the use of nuclear weapons in Ukraine. If they were seriously considering using said nuclear weapons in Ukraine, they would be unambiguously signaling through changing these documents and other such methods that other governments actually take seriously.

More to the point, breaking the nuclear taboo would be massively harmful to both Russia and Putins own interests. It would at best result in a NATO backed no fly zone over Ukraine while China and Iran completely abandon them, and quite possibly result in a direct conventional or nuclear war with Nato. I simply don’t buy that they would do that with no warning or previous signaling simply because an artillery rocket was manufactured in a different country.