TBH PRC "growth rate" is roughly in line with expectations, including PRC will overtake US projections from years ago, caveate being many of those projections assumed PRC would strengthen rmb to iirc 4-6 vs 7 to 1 USD to put PRC at ~25T economy. Regardless, GDP not particularly useful for comparisons of comprehensive national power.
> Lower growth and - maybe - some form of stagnation are more likely
The distinction is PRC doomers think PRC has peaked and will be declining soon. PRC collapcists narrative is about wanking at the notion PRC stagnating and never eclipsing US. VS relevant indicators suggest PRC is where JP is in 80s, where JP grew 400-500% until post 00s stagnation. PRC "stagnanting" at 3-4x the size of US is a much different geopolitical scenario than narrativet tha PRC doomers/collapcist want to push. Even PRC @2x larger is TBH in the "unmet expectations" column, but that's still relatively the largest country in the world by 2050 and more than enough to compete against US/west.
TLDR PRC is at 25% skilled workforce, and moving to 60/70/80% of advanced economies by generating 50-100m STEM + other high skilled labour in next 30 years. FOr reference US on trend to add 40m people total. PRC in process of reaping literally the greatest high skill demographic divident in human history, and why other East Asian countries continued to grow with shit TFR - they replaced unproductive talent with skilled talent. Stagnation comes when TFR can't replace productive workforce at parity, PRC has decades of headroom. Past 25 years = 250M births already baked into future workforce with system that disproportionatlly filters talent towards S&E.
The fundmental problem with PRC peak/stagnate narrratives, especially peak/stagnate below US, is deliberately presenting using very questionable suppositions (real estate, demographics, authoritarianism etc) to suggest it will happen soon instead of decades from now, with a PRC larger than it is now, and likely larger than US. Folks over indexing on PRC being good at overbuilding in real estate, tend to a turn a blind eye to that state overcapacity also applying to everything else - like PRC moving up science and innovation indexes, value chain etc - all of which is rapidly building PRC comprehensive national power.