Solar can be exported, for example, as pure hydrogen or potentially as hydrogen in ammonia, or possibly other easier to transport material (I'm not a chemist).
Places that receive high amounts of sunlight like Australia would also work for this.
As opposed to already tying energy needs to contested regions.
Now if we could somehow raise the price of coal to account for its externalities.. by stipulating minimum taxes on coal and imposing tariffs on any countries that don't implement those... then we might have a chance.
But I think wind energy (producing or importing) is probably Poland's best bet for getting off of coal.
I suspect doing it through economics alone isn't going to happen, instead some version of the Large Combustion Plant Directive will simply ban coal generation in Poland.