Leveling settled concrete pad
If you don't need all the vertical space, two options come to mind.
It would take about 3 yards of concrete to &quot;top&quot; that whole slab with a couple of inches of normal concrete, preferably fiber-reinforced. That won't be in danger of peeling off. However, if your concept of a workspace is LVP floored, the (presumed uninsulated now) concrete slab will be directly coupled to your floor, and that may be unpleasantly cold much of the year, and damp when it's less unpleasant that it's cold. Good if your workspace concept benefitted from a concrete floor, probably bad otherwise, and you seem headed for otherwise.
If raising the floor on sleepers, I would suggest raising the whole floor and insulating under it, rather than laying OSB directly or with moisture barrier (only) on the concrete on the &quot;flat&quot; side. That will give a floor that most people would consider to be more pleasant to live with, and may also reduce your heating bill somewhat, if you are in a climate that involves heating bills.