Soffit and ridge vents are still the gold standard for attic ventilation. If hou want a vented assembly. Unvented assemblies are fast becoming more used because they are more efficient. Cupolas are merely decorative on a modern built home.

Thank you Lomo and Mark.

I'll incorporate a cupola just to see if it works.

Mark: where would I find the necessary calculations to properly size the vents please.

Thanks again.

Cupolas are great for ventilation of a barn. For a home, I would suggest designing a central light well/ventilation system to include windows with thermostatically-controlled motorized openers.

Properly designed cupolas can be great for admitting natural light into the center of a house where there are no windows.

For ventilation, a properly sized and designed attic fan, with louvers which open when the fan is in operation and close when not, can significantly help ventilate a house and reduce the need for air conditioning. Of course, the air pulled into the attic from the house must have a means to escape the attic to the outside. In other words, a ventilated attic! It's an old fashioned idea, but it still works!

I'm about to self-build my own house here in Australia

Have you checked here: https://www.houzz.com.au

Thank you everyone.

I'm going to build that cupola!