Russia and Soviets have no comparision. Russia is using 5.5 and 6G aerospace tech in Ukraine. thats why Su-34 is called Super Stealthy in Arabic. while Soviets were always one generation behind US due to late start after World War 2. this one example.Soviet Union in terms of a similar, modern-era faster pace of decline and types of milestones.
Western Roman Empire in terms of the final outcome and fundamentals.
As I don't think there will be a reunification again as in Chinese dynasties, or even some form of a leaner, weaker successor, as a Russian Federation. There will be permanent fragmentation as after the WRE too.
UK also survived by latching onto the US as a first tier vassal due to their affinity, and I don't think the US will do that with China to survive and keep a certain level of prosperity.
the constraint on Russia is coming because fundamental transformation to a different religion has not happened.
you will need to study Arabic soft power to understand this personal attacks on Zelensky to reach some one else in indirect way.
this Kadyrov statement was made to give legitmacy to Crimea take over back in 2014.

Putin: Jewish Zelensky's cover-up of Nazi glorification in Ukraine is disgusting