tickPositioner property

A callback function returning array defining where the ticks are laid out on the axis. This overrides the default behavior of tickPixelInterval and tickInterval. The automatic tick positions are accessible through this.tickPositions and can be modified by the callback. Since v12.6.0, the callback also receives ctx as the third argument, so that arrow functions can access the same context as regular functions using this.

API Docs: https://api.highcharts.com/highcharts/chart.parallelAxes.tickPositioner