If you pay for things in USD for other people and demand to be paid back in RMB you will get a medal and thank you note from CPC for helping RMB globalization.With what money? All G7 governments are on deficit spending. There is one other way of doing it -- using foreign currency reserve. Essentially one loans out excess foreign currency (i.e. USD ) and gain debt obligation or bond that also can serve as reserve -- and you can even demand the obligation to be made out in another currency ( such as RMB ). This is what I suspect China is doing -- instead of financing US, transmutes the excess reserve into RMB denominated instruments. None of the G7 has a sizable reserve except Japan, but US need Japan to prop up USD. Although Germany also has sizable trade surplus, it's in Euro so does not need to keep it in reserve, nor does it need to keep a sizable reserve like Japan. The neat point is that China does not need to budget BRI from the state budget, while G7s do if they want to counter BRI. Note they cannot print money either because inflations everywhere are increasing and there is a limit to how much cash an economy can withstand.
You can't print USD to fund this: the aim of this whole thing is to compete with BRI and it's 3.8 trillion USD worth of infrastructure already built and increasing. If you print USD then there will be inflation and price of everything will increase, including the value of that 3.8 trillion BRI infrastructure. I can give you 40 trillions in ghost money but it wouldn't allow any roads or ports to be built, and in the end it's the physical infrastructures that people are looking for.
Japan's GDP is about 5 trillion, it has 14 trillion in national debt which is already pretty crazy. If we spread out the 40 trillion equally among the seven of them that's 6 trillion each. Can you imagine Japan increasing its national debt from 14 trillion to 20 trillion for this?
Neither the money side nor the supply side supports this 40 trillion dollar plan, which is why the whole thing is so laughable. If they instead said 4 trillion I would actually be slightly worried.