Carbon dioxide is best in a range similar to what was around in our atmosphere about 50-100 years ago. Too little and it can get too cold, too much and it can overheat.
Even so, I think the cause and effect relationships are not as straightforward as climate science nowadays claims, a warmer earth will also produce more carbon dioxide from the increasing areas covered by vegetation.
I would rather take my chances with a bit of extra warmth than in the other direction, cold climates are more of a potential danger than warm ones.
During that snowball earth episode, a lot of the world’s land was near the equator. You would think that could be a good thing for a fairly high average global temperature but the Sun was not putting out as much heat then as it does today, and once the balance tilted towards glaciation of higher portions of the land, it quickly went out of control and froze over the whole planet. I’ve read that the earth could have stayed in that state for a long time but volcanic activity increased greenhouse gases and once the ice began to recede, by then solar output had increased a bit and these global glaciation conditions never returned. The ice ages we have now are started by a different process, glaciers near the poles expanding towards lower latitudes. Those see to be controlled by the various orbital factors which are currently in a neutral but inter-glacial setting. If we weren’t warming up the atmosphere slightly, it would be cooling very slowly but not at a rate to concern us about an ice age, that could be 25 to 50k years into our future.