Post WW2 Lithuania-Belarus-Kaliningrad single state

[Vistulian]

In 1945, the Soviets formed the Federal Soviet Socialist Republic of Lithuania-Belarus with the capital in Vilnius, the Kaunas ASSR grouping Baltic-Lithuanians and the Konigsberg / Kaliningrad oblast. This is formally motivated by the collaboration of Lithuanians, the restoration of the historical relationship between Lithuania and Belarus, and the need for effective state management, which requires access to the sea. The ports in the Kaliningrad Oblast are given a similar status to Sevastopol in the Crimea.
How are the relations in this republic? Does the USSR collapse if Latvia and Estonia are territorially "locked"?
What is Lit-Bel's policy after 1991, assuming it remains interconnected? The country has some 14 million citizens.

 

[Dingus Khan]

Would such a hypothetical state try to join EU and NATO after the fall of the USSR?

 

[Otto Kretschmer]

Most people in such a country will be Belarussians. As of 2021 there are 9 mln Belarussians and 2.7 mln Lithuanians

In the times of PLC those two did not have much in common. There were only held together by common Polish speaking elite.

Most likely the country would split up upon collapse of USSR. Alternatively, this may hasten Russification of Lithuania due to higher population mixing