“Russians, Ukrainians, and Belarusians are all descendants of Ancient Rus, which was the largest state in Europe. Slavic and other tribes across the vast territory – from Ladoga, Novgorod, and Pskov to Kiev and Chernigov – were bound together by one language (which we now refer to as Old Russian), economic ties, the rule of the princes of the Rurik dynasty, and – after the baptism of Rus – the Orthodox faith. The spiritual choice made by St. Vladimir, who was both Prince of Novgorod and Grand Prince of Kiev, still largely determines our affinity today.”

That’s from this July 2021 essay by Putin - http://en.kremlin.ru/events/president/news/66181

His ultimate vision is reunifying the Russkiy Mir. There’s definitely the will do so amongst the nationalist parts of the population. Whether that’s practical is another question.

Regime change in Russia should be discussed more, but in the context of Russians deciding it for themselves as opposed to foreign powers. More incentives and pressure to do so should be considered. It’s the only way to end this war in my view without further escalating it beyond Ukraine to countries like Moldova for example.