if you have the web dev module, I recommend using chart.js from a doGet embeded in a iframe just this week I had to do something similar and it came out looking like this (had to block out some data)
you can also check this module out if you don't have web dev. it will allow you to use chart.js charts in perspective
personally, I find ignitions built in charts to be limiting and try to avoid them. that being said if you have to use ignitions charts check this documentation out it should show you how.
XY Chart Example - Gantt Chart | Ignition User Manual