[college_physics]

Its possible. Its called sovereign money. You basically have an account with the central bank just like private banks do (but they dont want anybody else to have)

These accounts pay strictly zero but can never default.

Anybody who wants to get a return can deposit with a private bank but then they need to monitor that bank because if it mismanages risk they are on the hook.

The thing to understand is that private banks are experts at risk free profiteering and passing the buck, not at managing risks which is really hard work

The monetary system is an absurd and unfair anachronism and it lurches from disaster to disaster.