> religious persecution of non-Catholics

There was some of that (especially in lat 1600s), but compared to basically any other country at the time it was significantly better. PLC even had a law that each newly elected king had to sign where he promised not to persecute anybody because of religion or he stops being the king: https://en.wikipedia.org/wiki/Warsaw_Confederation

Majority of magnates (the big nobility that actually decided things by buying other nobles during elections) weren't Catholic in 1500s.