China is winning in merchandise trade, but you're right cos that's only the beginning, the game is far from over yet. There are services trade, and then there are investment or financial which is the real game changer.
Yes China is hoarding too much dollars, as of 2021Q2 our reserve assets ($3.3459T) still account for as high as 37.06% of total international assets, though this ratio has dropped from above 50% at its peak, we are still far more vested than major creditor nations say Japan's 11.84% (2020Q4). We are actively pivoting to outbound FDI, in order to do so we have build a couple of SWF (sovereign welfare funds) following the successful path of Kuwait, Singapore, Norway etc, but we face severe hostility in cross-border M&A especially in the west, we can only progress gradually. Dollar hoarding is in fact a catch 22 situation for China, it needs to be carefully managed for the time being in order to keep currency exchange rate stable, but the roadmap is clear.
www.mof.go.jp