If you overdo it you get inflation, that's why it's the typical central bank target.
Previous recession happened for other systemic reasons, like subprime mortages bubble bursting bringing down with it a lot of other things. Unemployment was more like a temporary consequence of that and necessary changes/realignment of expectations/allocation of money in the economy.
"How the Economic Machine Works" https://youtu.be/PHe0bXAIuk0
Increased (or trying to artificially increase) economic activity (as measured by GDP) is also not good by itself, but only in relation to meaningful demand.
Otherwise, digging and filling holes (like in a war, basically) would be an overally good thing, which it is not.
There's no need to increase spending via a central bank currency manipulation, just because it's lower than before, nor is it the only way to achieve that.
And money printing (lowering interest rates, QE, helicopter money, fiscal stimulus like New Deals or the likes of building the Hoover's Dam) is a generally acknowledged consensus on how to at least try to fix it. That is how to at least try to make people transact more.