Is play sand suitable for sanding or topdressing?

No, play sand isn't suitable for that.

Play sand typically contains clay, silt, or silica. These components ensure that the sand retains its shape and is easy to mold—which is useful for sandboxes but problematic for the lawn.

When sanding or topdressing, the sand is intended to loosen the soil, improve water and air permeability, and reduce compaction. Playground sand, however, has the opposite effect:
It leads to additional soil compaction and, in the long term, degrades soil structure.

For topdressing and sanding the lawn, you should therefore use only suitable lawn sand that is free of binding agents and improves soil quality over the long term.