Since nobody else has posted it, here’s a common list of fascist traits:

• Powerful and continuing nationalism
• Disdain for human rights
• Identification of enemies as a unifying cause
• Rampant sexism
• Controlled mass media
• Obsession with national security
• Religion and government intertwined
• Corporate power protected
• Labor power suppressed
• Disdain for intellectual and the arts
• Obsession with crime and punishment
• Rampant cronyism and corruption

It’s not the be-all-end-all definition, but it’s a good guide. The USSR checked a lot of those boxes, but two big ones it didn’t were intertwining religion and government, and protecting corporate power. Arguably, those are because religion and corporations became part of the state, though. The USSR was also generally very keen on science and the arts, but only as long you didn’t do anything subversive.

I’d use the term authoritarian myself, but there’s enough meat on the bone that you could argue for fascism.