Your term 'money' needs to be defined. Marx defines three values: use-value, exchange-value, and surplus-value. 'Money' as you define it, I assume would be exchange-value. There would be no need to return money to a central bank because exchange-value can be created or destroyed.

I'm not an economist, but capital can be created and destroyed as needed. The stock market is a good example. Currently capital is being destroyed to slow down inflation. Real estate (capital) prices are declining.

Marx was wrong about 'labor' being the fundamental creator of value. Since the industrial revolution, and now in the information or knowledge based economy 'production' is the main driver of value. During the industrial revolution labor was automated and turned into production. Now everything is being automated so production becomes independent of labor entirely and often destroys labor and jobs.

You are thinking the problem is the economy is not self-regulating, and the solution is to give money back to the central bank? I would say the problem is over-production: production for production's sake, to create more capital and wealth. We need to return to a world where we produce just enough, and this would self-regulate the economy.