The onBeforeCardRender event is now available in the latest sandbox build (2025.2.6497).
You can change the bar color depending on the column like this:
onBeforeCardRender: args => {
switch (args.data.column) {
case "1":
args.data.barColor = "#ea3624";
break;
case "2":
args.data.barColor = "#1155CC";
break;
case "3":
args.data.barColor = "#999";
break;
default:
console.log("Unknown column: " + args.data.column);
break;
}
},