Hello,
It was necessary to add the logic of checking whether the nodes are inverted and take it into account when drawing the line. Here comes another problem, the labels are centred based on the line length and if you draw the arrows are not in the center, you would have to override the function responsible for these calculations.
But it is starting to become a very custom functionality and it goes beyond the scope of the support. If you need help with your implementation, you can try to look for it on the more general forums like StackOverflow or contact the Black Label company that specializes in Highcharts custom projects. See the official Black Label site:
https://blacklabel.pl
Demo:
https://jsfiddle.net/BlackLabel/7mt5cz1g/
Regards!