Watch Russian state media. Literally stuff they say...
That's possible, but I think they just use the rhetoric to activate old people nostalgia and bring more support for the regime. Soviet union respawning does not seem likely, nobody except Russia wants that.
Any reason to think this? Did Soviet Union form by Russia invading and conquering another country? No, it was a result of fall of the Russian empire and the Russian civil war.
The conditions now are very different. Fall of Ukraine would mean political win for Putin and his acolytes, maybe another invasion later on. But Soviet Union? More like stronger Russia, a revert to the Russian Empire.