Fascism is the merger of corporate and state, where there is no longer a distinction between church (moral) and state (executive) functions. This tends to be implemented in ethnic or linguistic hegemonies because pluralistic societies are inherently more decentralised. But there is no reason per se that fascism and ethno-nationalism need to synonyms, this is just an accident of our associations, and an unfortunate one. Ireland is an ethno-nationalist state, as was Greece. They weren't propositional nations as the modern revisionist history suggests. Why were Greece of Portugal fascist but not Ireland? The difference comes down to the level of corporate integration with the state, not the ethnic dimension. Arguably South Korea and Japan are fascist today, and have been since WW2, not because they are ethno-states, but because they are deeply centralised and governed by large corporate administrations that dominate every aspect of people's lives.

Due to the heavy hand of regulation and the purchase of democratic institutions by corporations we have a deep integration between the corporate and the state in the West.

China today is definitively fascist, the CCP being the closest thing to a Nazi party in the modern world. This is not disputable, communism failed and fascism picked up the pieces, enslaving the population through new corporate vehicles barely distinct from the state.

The USSR attempted communism, but when it collapsed it veered wildly towards anarcho-capitalism, which then re-centralised to an extent, but it is nowhere near as centralised or fascistic as China and the CCP.