I hear what you are saying, but I still do not understand you.You are forgetting one thing. It's generally not smart for firms to take currency risk. That is the equivalent of gambling.
The main reason why countries are forced to hold dollar reserves is to avoid a suddenly uncontrollable depreciation of the currency. During the 1990's Thailand had higher interest rates than the US, just like China today. As a result, companies borrowed in USD to finance domestic expansion. But when the Thai baht came under speculative attack, it suddenly sank, and Thailand did not have enough USD reserves to prevent it. As a result, all the Thai companies could not pay off their debt and went bankrupt.
Thus, if Chinese companies avoid dollar denominated debt (except those that can afford to gamble), then China does not need to hold as many reserves.
In general, the less entities hold dollar debt, the more we move away from a dollar basted international system.
1. A Chinese firm, they would normally get loans such as borrowing USD to open a factory somewhere.
Why would a Chinese factory buy US bonds? That kind of makes no sense. US Treasuries pay no interest. Any Chinese company with cash should be expanding their business inside China with more investment.
2. If all you want to say is that Chinese entities should avoid the US Dollar, well, that is all is required to be said. No need to say anything else or bring up the issue of debts.
Suppose that same Chinese company wants a loan, but decides to go to some investment banker and issue a bond for sale priced in RMB. China, like most countries, have bond markets (normally reserved for the 1% like the the members of the Trump conspiracy).