From what I recall on the subject, the soviets took it.
For several years after the berlin wall came down I had an email exchenge with an East German who knew a lot of WW II history at the end of things and he was convinced the Bernstein Zimmer was still hidden in Poland or East Germany. He schooled me in a lot of things that later were proved to be true.
He disappeared about 10 years ago from our conversations. Maybe he found something. He and his friends with metal detectors were always looking.
Amber burns. It is generally accepted that it burned during the fighting.
There was a book that came out (maybe a decade or more ago) that found evidence (including the original report of the head “antiquities officer” that accompanied the Soviet forces into Konigsberg) to indicate that it had been destroyed in the fire that consumed Konigsberg Castle during the battle.
The authors concluded that the Soviets had kept alive the rumor of the “missing” Amber Room to use as propaganda against the West, and also because it was simply too much to consider that one of Russia’s greatest art treasures had not only been stolen and destroyed, but from all indications it had been destroyed by Russians.
Either the Communists took and hid/destroyed it, or it was destroyed when the Konigsberg castle burnt by the Communists.
Warehouse 13 in the South Dakota Badlands
Russia should sue Germany. That level of theft is not part of war.