> I noticed years ago that majority Catholic and Orthodox countries are generally less prosperous than Protestant countries

Based on what? I can't think of a single pairing of Protestant and Catholic/Orthodox countries that genuinely had a similar enough history, geography, geopolitical situation to be able to compare them easily. Maybe the closest would be Belgium and Netherlands, but even then Belgium spent a few hundred years more under a faraway empire milking them, and as a frontier for lots of fighting with the French, and occupied by the Germans. And Belgium is also smaller in land and population, and had a very different colonial way of working. It also had resources (coal) that allowed it to industrialise quickly, while the Netherlands didn't so focused mostly on trade and trade posts.

And... Belgium has a slightly worse economy by most classic metrics (GDP, GDP per capita, etc.).

Maybe the only other even remotely comparable countries with different religions are the Baltics (Estonia was Lutheran when they were religious, Latvia is very mixed, Lithuania is mostly Catholic). Estonia and Lithuania have pretty similar GDP per capita, with Latvia a bit behind.

But seeing this through a religious lens is missing the forrest for the trees at best.

The book examines this in multiple different ways, not just at the national level, but even within countries (provinces that are more catholic vs more protestant, and even within Germany, how far the city was from Wittenberg), as well as comparing third world countries that encountered catholic missionaries vs protestant missionaries.

Trust by Francis Fukuyama explores this relation if you want more meat than comments on a board.