If the Russians invade the NATO Baltic states, NATO should overrun Kaliningrad as the first order of business.
During congressional testimony in February, Gen. Philip M. Breedlove, the NATO commander, described Kaliningrad as a “very militarized piece of property” and a “complete bubble” capable of repelling attacks by air, land or sea. ...
Given [Putin's] stated policy of safeguarding ethnic Russians who were severed from the motherland after the Soviet Union disintegrated, some fear the next target might be the Baltic States: Estonia, Latvia and Lithuania. All three former Soviet republics are now members of the European Union and NATO.
An attack on them would trigger NATO’s mutual defense treaty. Any attempt to defend them would have to get past Kaliningrad, wedged between Poland and Lithuania. ...
Any NATO forces attacking Kaliningrad “will get their teeth broken,” one gruff [Russian] angler said. A navy veteran, he stood beneath a symbol of Russia’s might and glory: a hulking equestrian statue of the Empress Elizabeth Petrovna facing the West.
I don't recall the Soviets fretting over West Berlin during the Cold War. The Western garrisons (a brigade each from America, Britain, and France, if memory serves me) would have died hard, but they would have died, if the balloon had gone up.
The Kaliningrad garrison should face the same fate as West Berlin would have endured if Russia launches a war on NATO. It should fall.
So yes, a counterattack from Poland into the Baltic states would have Kaliningrad on its left flank, but that's more reason to wipe out that enclave first. That cleans up the left flank and paves the way for NATO naval and marine forces to operate against the coastal flank of the Russians controlling the Baltic states.
Besides, owning Kaliningrad would be a bargaining chip on NATO's side as the looming threat of nuclear escalation raises its ugly head in a conventional war between nuclear powers, pushing us to a ceasefire perhaps before NATO can mass the forces to begin a counterattack to free the Baltic states by force.
Stop fretting about what the Russians can do to us with their Kaliningrad enclave, perhaps imagining they are "suddenly going to turn a double somersault, and land in our rear and on both of our flanks at the same time," and focus on what we can do to the Russians.