The Polish expansion with took place in the East in previous centuries was chaotically accidental.
Mostly on request and exchange of services, most likely as a form of securing own investments and pushing for a more agricultural society (especially Ukraine) to increase wheat exports to western europe).
Nowadays Poland has enough internal problems from the need to develop and invest it's eastern regions.
Occasional raiding and plundering reduced to a threat of illegal immigration that doesn't respect the rule of Poland's laws.
Otherwise foreign motor gangs and states like Belarus have not much influence or possibility to threaten Poland.
Lithuania, Germany, Czech rep, Slovakia are on relatively friendly terms and Sweden has no reason or wish to interfere in Poland.
So only possible threat is from Russia in a military/special operations forms.
And while Russia is stuck in Ukraine, it delays any possible invasion of Poland.