Looks like this is general problem with chart components, they do not accept CSS variables.
Theme color variables in Piechart are not supported? - Ignition - Inductive Automation Forum
Perspective Css-Theme-Variable not working on all Controls - Ignition - Inductive Automation Forum
[BUG-1512] SimpleGauge color props do not accept "named colors" from theme variables - Ignition Early Access - Inductive Automation Forum
You can try ApexCharts.