2019 Australia's Hottest and Driest - WMO, page-41

Seeing that humans ( ie Homo sapiens ) only really seem to have started around 500,000 years ago (and that is not when they were thriving , which would be only in the last 10-15,000 years ) , then the CO2 levels were about 200 ppm from your graph.

You stated that we could line in 2000 ppm,
and I have shown that we were not around then.

So the proof is up to you to show that we can survive at 2000ppm

BTW Dont forget to include all the other Biosystems we rely on to thrive .