You can implement marker selection through click events and controlled props. Here's how to do it:
Using onItemClick and Controlled Selection:
import { ScatterChart } from '@mui/x-charts';
import { useState } from 'react';
function ChartWithSelectableMarkers() {
  const [selectedMarker, setSelectedMarker] = useState(null);
  const data = [
    { id: 'point1', x: 10, y: 20 },
    { id: 'point2', x: 15, y: 25 },
    { id: 'point3', x: 20, y: 30 },
  ];
  return (
    <ScatterChart
      series={[
        {
          data: data,
          label: 'Series 1',
          color: (params) => 
            params.id === selectedMarker ? 'red' : 'blue',
        },
      ]}
      onItemClick={(event, params) => {
        setSelectedMarker(params?.id);
      }}
      width={500}
      height={300}
    />
  );
}