As far as I can perceive the reasoning, I understand that growth is the entire foundation that upholds the dominant economic construct... No growth, no sustainable economy.

This is exactly why we need to build another economic construct. I don't believe the present one is long term sustainable. All physical systems have conservation laws, I don't see how the economy, being based in a physical reality, could not be limited by conservation laws as well. Thermodynamics will get us all. I would be interested to hear someone attempting to explain why economic systems are not subject to conservation laws that prohibit indefinite growth. Is our system not physically based? Even stuff like "intellectual production" would have to be limited by only having value compared to other "intellectual assets". Sounds very much zero sum to me. So, any "growth economy" proponents here on the trib? Why is it that this is a physically possible system?

Is there such a thing as sustainable growth?

Yes, it's called inflation.