why Plotly.react() is as slow as Plotly.newPlot()? updating single trace of many

Hi, I am trying to redraw only single trace in a plot of many traces (biophysical data). I tried to follow instructions in react-plotly and plotlyjs documentation:
https://plotly.com/javascript/plotlyjs-function-reference/#plotlyreact
Plot is updated but I don't see any performance improvement if I change only single element of data or all data elements:
Here is MWE in codepen
Briefly, I generated sample data 100 traces of 10000 points and changing only first trace with:

  data[0].x =  [...Array(10).keys()].map( c=> c/10) //change only first trace
  data[0].y =  [...Array(10).keys()].map( c=> Math.random())
  Plotly.react('myDiv', data, layout);

Drawing plot containing single trace takes just a split of second, but if I had already drawn many traces and I want to redraw only single trace, it takes same time as to redraw all traces (few seconds).
Am I doing something wrong?

Start with the linked CodePen MWE and compare Plotly.react() with Plotly.newPlot() using the stated 100-trace, 10,000-point data. Read the linked Plotly.react documentation and trace the update path in the repository; the issue names no source file or test. Done would require identifying the cause of the comparable timings and defining the expected optimization or documentation change.