While easy to argue the semantics and historical benchmarks of what constitutes a "World War". I've always considered the current large scale state of digital warfare, disinformation campaigns, election interface, digital espionage, cyber attacks on critical infrastructure, etc among all major powers an ipso facto act of war and non-traditional declarations. Combined with pockets of conventional warfare often fought via proxy. I view it already as a world war 3 state, with the battlefield shifted across wires instead of fields and trenches.
Government regulations and restrictions on Internet usage across the world have been pushing more and more towards a geographical intranet with carefully selected internet access. China has been doing this for over a decade to control information and trade protectionism, with a good number of other countries following suit. Western countries are slowly pivoting that direction as well with a 'boiling frog' strategy.
Many people equate a declarative WW3 with the launch of nuclear devices but the moment they start flying, it's no longer a world war, but a likely mass extinction event. At that point, there is very little to anything you could do.