I am trying to navigate in the chart with the accessibility module, but to move within the line or bars I have to navigate with the help of Alt + (up, down, left, right) not directly by arrow keys.
Also unable to find ay explanation for that as well, if anyone can suggest some reason or correct course of action that would be really helpful.
For sample, this chart also behaves in the same way with NVDA https://www.highcharts.com/samples/highcharts/accessibility/accessible-line
I haven't worked with highcharts before but do you have access to the HTML it generates? You can get it to work by adding role="application" to the <div> that contains the main <svg>.
<div role="application" id="highcharts-i7l4x35-0" class="highcharts-container " aria-hidden="false" tabindex="0">
<svg version="1.1" class="highcharts-root highcharts-legend-series-active" xmlns="http://www.w3.org/2000/svg" width="820" height="420" viewBox="0 0 820 420" aria-hidden="false" aria-label="Interactive chart">
<desc aria-hidden="true">Created with Highcharts 9.2.2</desc>
...
Just be careful with role="application". It should be used sparingly.