China will become the #1 before this decade ends.
This is as certain as the sun rises in the East.
It depends what is meant by #1 or dominant world power. China is already a dominant world power, as is the US and Europe. But China cannot become THE dominant world power for several reasons.
China is a homogeneous country with little experience composing with diversity. Which leads to another reason, that's it's a dictatorship and thus not willing to compose with diversity. China attracts few other than on a purely economic level and to be THE, a nation must inspire.
Militarily China is very powerful, but its rigid hierarchy precludes it from establishing meaningful relationships other than strictly economic or through domination. 1 China (and North Korea) cannot subjugate dozens of nations, which includes mighty ones.
As is being discussed, China has a steep demographic problem with a 50% decline by 2040. Although the 1 Child policy of the 60s is dead, its consequence will be felt for a long time. Furthermore, China's prosperity is leading to fewer children, regardless of government incentives to have more. Demographics is China's greatest threat, not the US.
China has an astounding number of scientists, engineers and researchers who have nothing to prove to the world. Their contributions will be key in improving the lives of the world's population.
It seems absurd to risk everything on an ego quest to reclame Taiwan from their Chinese family. Then again, look at Russia and Ukraine....