A digital Yuan subject to borderless trade will allow the inflow of money into the Chinese ecosystem that has been previously restricted.

It would also allow the reverse, and that is the reason why it will not happen. I'll stake a year's salary on that. China is, and always has been terrified of capital flight because the Party is irrationally fearful of anything that they cannot shut down at will, especially high amounts of their citizens' money in foreign banks.

It seems that China holding the title of the world's largest GDP is a matter of when than if.

Again, math disagrees. Even if China's GDP grows at 6% annually (and no economist outside of China predicts a figure this high, in fact very few even believe it has been this high for the past few years), and the US only grows at 3%, it would still be the year 2100 before China caught up to the US at those growth rates.
Begin from China's 15 trillion dollar GDP and the US's 22.5 trillion dollar GDP and extrapolate them both forward at the annual growth rates listed above and count it, and that is even if China managed to continue 1 6% annual GDP growth perpetually (which no nation has yet managed to do once they reach the "Middle Income Trap").

China will be the primary beneficiary as they are the world's top exporter

This too is incredibly unlikely to still be true a few years down the road. China's primary customer, accounting for more than 65% of their exports, is the US, and the US is actively curtailing purchases from China while China currently has no cost-effective way of sending goods anywhere else. Solving this dilemma is the goal of the BRI, but so far it will be at least a decade before this project gains enough cohesion to actually amount to the right level of transport infrastructure to make it possible for China to replace their primary customer.

5 years from now, China will be a spent force that cannot even compete with a newly resurgent Japan. I say this from five years of living in Beijing's capital and diligently studying every aspect of China's economy from the inside.

• China can't even feed their own people.
• They are earning a global reputation as barbarians.
• Their diplomatic approach is costing them what few allies they had in the Pacific Basin.
• Their signature project is being seen for the farce that it is.
• They are making enemies on every side.
• They are provoking an alliance of Great Powers that they cannot hope to beat any one of, let alone all of.
• Even small nations are not afraid to stand up and tell them to P!$$ off
• Their long-time arch-rival is beginning to lose patience with their constant aggression.
• The nation that has long been the only thing propping them up, namely the United States, is throwing their hands up and saying "I'm done with you."
  And of course...
• They're flirting with the possibility of an apocalyptic epidemic.

China's dreams of superpower status have been dead since 2015, and ironically enough, the only place in the world that still hasn't realized China is crashing... is the West.