You are overcomplicating this. Poland is nepotist kleptocracy, EU and NATO membership away from Belarus. They should adopt euro since yesterday, it's strategic goal in line with membership in EU and NATO.

Switzerland can have their own currency, where inflation over 2% is a scandal. Sweden can have their own currency, they produce their own cruisers, submarines, fighter jets, and artillery. Poland kicked out their last baby boom into emigration and now have the same demographic and immigration crisis as geriatric Italy and Germany. They have nuclear power plant company operating with its board receiving executive salaries for fifteen years now and... no nuclear power plants. Accumulated inflation since pre Covid era is 43% and doesn't look to be stopping. Own currency enables enormous fraud and creates class of oligarchs.