The heating alone would do that, yes. It’s the knock-on effects. As CO2 rises, the ocean slowly acidifies. As the ocean increasingly acidifies, oxygen producing lifeforms (approximately 70% of the oxygen we consume is produced in the ocean) increasingly die out. The Amazon Rainforest (a large producer of oxygen on land) is on fire. What will we breathe? It’s an ecological apocolypse, not merely from getting hot (which your comment seriously underestimates the direct effects of) but from the previously mentioned oxygen crash, and hundreds of other effects that we know about and can reliably predict.