\version "2.22"

\new PianoStaff <<

  \new Staff = "right" {
    \once\override Slur.details.edge-attraction-factor = #1000
    \once\override Slur.eccentricity = #-3.5
    \once\override Slur.height-limit = #7
    \once\override Slur.ratio = #0.15
    e'''2 (
    \change Staff = "left"
    
    a,,4 ) % this slur does not end in the second stave
    \change Staff = "right"
    
    b''8 r |
  }
  
  \new Staff = "left" {
    \clef bass
    s1
  }
  
>>