I will find you the sources once I have time.
And reread my post, I never said HRE was ever like a dynasty; I said that HRE thought themselves as Romans and an embodiment of Rome even thou they are not; just like many people nowadays think themselves as Han, and they are not.
And I know my history well, religion is not a good indicator of cultural inheritance. If you have been to Egypt, you would know, people are more prideful of being Egyptians, the decedents of the Pharaohs instead of being the decedents of Islam.
You also do know that the Russian Empire is larger than the Soviet Union; the laregest extent of the russian empire is 23.7 million square km, while the USSR was 22.4 million square km. Hence, your statement is wrong