Whether or not they overtake the US in overall output, the growth is already tapering off. They've become a developed economy, with a quickly growing consumerist middle class and service sector, and also quickly growing demand for higher wages. The old export-based growth model based on cheap Chinese labor is becoming a thing of the past, and so is the associated growth trajectory.
I've seen many notable projections also about China and Russia no longer being countries by 2028 (eg splitting due to war or civil differences) which is something I think we'll see a large pressure on a split at some point (especially in china).
Really? The CCP seems stronger than ever. Honestly, civil war seems more likely in the US. (Not that I think that's likely either)