It's common to hear people in the US media lament the $1 trillion debt that's owed to China. This 'debt' is nothing more than $1 trillion in savings that China has in their account at the Fed.

You are correct to say that it's not a true reflection of the host nation's savings, but data exists to help you figure out that amount.

If the savings will continue to be saved (including the interest), then I don't think it will make the kind of difference that you're thinking of. If the savers decide to spend the money, then things will change.

You're also correct that banks create money (well, credit that gets used as money). However, they don't use the fractional reserve model that you see in textbooks and You Tube videos. Instead, they use something called the credit creation model. In a nutshell, banks can create as much credit as they like (with fewer constraints than fractional reserve). What matters to them is whether or not they can find credit-worthy borrowers.

Bitcoin is a form of 'acknowledgement money' - it acknowledges the fact that someone did 'work' to mine it. However, unlike work that you or I do, the acknowledgement that Bitcoin provides lasts forever and doesn't diminish over time (though the price fluctuates). The credit money that banks create gets destroyed when it's paid back to banks, just as the money (effectively tax credits) that the central bank creates on behalf of Government get destroyed when paid back to the Federal Government in taxes.