Blanking staff lines using the \whiteout command
The \whiteout command underlays a markup with a white box. Since staff lines are in a lower layer than most other grobs, this white box will not overlap any other grob.
\version "2.24.0"
\layout {
ragged-right = ##f
}
\relative c' {
\override TextScript.extra-offset = #'(2 . 4)
c2-\markup { \whiteout \pad-markup #0.5 "middle C" } c
}