As I've already mentioned, no, Romanians weren't free. WW1 liberated them. Really liberated them unlike WW2 with its Russian Liberating Army.

I'm gonna ignore your whataboutism. The American states were colonies of the British Empire. They thought, became free, then united. End of story.

Yeah, I sort of forgot about the Mongolian empire because I ignore it most of the time. Nevertheless Wikipedia estimates its peak size at 23,500,000 km² while USSR had 22,402,200 km², so they're pretty close.