Only of you ignore CO2 and other environmentally damaging emissions that stem from needing to feed and push millions more people out of poverty into the middle class where they also start to consume and travel and produce emissions.

So yes, the planet can theoretically sustain billions more people but only if you look at planetary free square footage per capita, but at the cost of either them living in absolute poverty, or insane environmental damage and climate change which will also create poverty from the issues climate change will cause to agriculture and food prices, so we're back to millions living or dying in poverty.

Canada and Australia are huge countries but the livable parts are quite small. You can't have infinite growth on a planet of finite resources.