[Chartjs]-Chart.js Show label/tooltip for single point when multiple points coincide

Use the afterBody callback to manually adjust what the tooltip is going to show by removing all but the one point that you want to show. https://www.chartjs.org/docs/latest/configuration/tooltip.html#tooltip-callbacks

You can filter tooltips using knowledge about the entire dataset

// ChartJs version: 3.7.1

tooltip: {
  filter: (item, index, list) => (
    item.parsed.x !== list[0].parsed.x &&
    item.parsed.y !== list[0].parsed.y) ||
    index === 0
  )
}

// ...

Screenshot