Hi,
You missing set yAxis.categories
Like documentation says Applies only when the axis type is category.
Here's another example where points are adjusted for cell height, test it for yourself.
https://jsfiddle.net/BlackLabel/9rpozfuj/
API References:
https://api.highcharts.com/highcharts/yAxis.categories
Demo:
https://jsfiddle.net/BlackLabel/9rpozfuj/
Best regards.