Welcome to our forum and thanks for reaching out to us!
Unfortunately, there isn't any option available in Highcharts Gantt that allows to layout tasks paralell, as it is related to inability of setting each row height. There is a similar topic on forum that covers this subject: viewtopic.php?f=19&t=50754
As a workaround, you can use this solution that adds breaks to y-axis in order to create enough space for the tasks, and then moves the collapsing points, so that they are spaced out parallel. Note that this solution isn't fully tested and probably would require some customization.
If you believe that such option should be included in Highcharts Gantt, you can post a feature request on GitHub repository: https://github.com/highcharts/highchart ... .md&title=
. The more people that upvote, the closer we are to seeing this idea become a reality.
https://api.highcharts.com/class-refere ... #translate
https://api.highcharts.com/class-refere ... xis#update
Let me know if you have any more questions!