I’m sure Lithuania would love to have Kalingrad oblast back. It has a nice little bit of coastline and this is of strategic importance. Russia craves Baltic coastline real estate (nice and ice free) and if Lithuania had it back, it would be a setback for the Russians. How would Poland feel about this?
The Poles have already proven how they have the will and the might to kick the Russians back to the East when the Nazis are not grinding them down from the West.
Putin isn’t stupid. He knows there is age old hatred for Russia among the Poles. He sees how Poland is keeping Muslims out and fighting their attempts to infiltrate.
Let Putin build his military cathedrals.