You can, if leverage is being used through bank loans (which create new money) or if the central banks pump money into the markets by purchasing trillions of dollars worth of financial assets.

Or another way that the net returns are positive is that the companies actually make profits and pay them out as dividends.

That would cause hyperinflation (like the Weimar Republic, Zimbabwe and Venezuela), because it is being used for consumption of existing goods and services, rather than for creating new goods and services.

There is an easy way to avoid this. Basically what you have to do is to print just enough money to reach a certain target (for example a target might be 2% deflation, 0% inflation/deflation, 1% inflation, 2% inflation, etc.). Use whatver you have printed to fund the government. If it is not enough to fund the government, get the remaining money from taxation. If you have a surplus, then pay back any debt.

Printing money to fund the government will indirectly create new goods and services. If you print money to fund government, then less taxes will be collected. If less taxes will be collected, then more money will be in the hands of people and buisnesses, which will likely be invested and create new goods and services.