Up-down bow

Combined up and down bow over a whole note using a little script:

\version "2.24"

updownbow =  -\tweak parent-alignment-X #CENTER
  ^\markup \concat {
    \musicglyph #"scripts.upbow"
    \hspace #0.3 % tweak space to your liking
    \musicglyph #"scripts.downbow"
  }


{
  c''1^\upbow
  c''1^\downbow
  c''1^\updownbow
}