Around Seattle, modern houses are square boxes with a flat roof, and zero eaves. I watch these homes get built all the time. A few years later, I see all the water damage to the siding.

You're right about ridge vents, they behave much like a cupola, but the holes in them are too small for much airflow, and are easily blocked by debris, insects and moss.

> easily blocked

That's a concern. It may be a good idea to put a connected thermometer and hygrometer in the attic. If it is ventilating properly, the temperature and humidity should be close to outdoor values.