I think you have a fundamental misunderstanding of how budget deficits work for nations that have sovereign fiat money. At a minimum, read up on modern monetary theory.
And when I’m talking about deregulation, I mean deregulation of financial markets, externalities produced by corporations, labor laws, etc. Those checks on capital that have protected the working class have slowly eroded over the past several decades due to the dominant ideological consensus of neoliberalism.
Left and right are not meaningless terms despite being more nuanced than a mere two dimensional spectrum. You can have authoritarian “socialism” or libertarian socialism just as you can have an authoritarian fascist regime or some kind of libertarian free-market system (although I think those will collapse into the same thing). Just because concepts are complicated does not make them meaningless.