How to create widget in a single AWS Cloud Watch dashboard for a list of instances

Terraform (aws provider) beginner here. I am trying to create aws-cloudwatch widget that graphs CPU Utilization for 3 instances. However, I only get one graph generated for the last instance in the list instead three graphs on one widget! How can I fix this please or get this How can I get this code to create CPUUtilisation graph for three instances on the same widget? Thank you

variable "targets" {
default = ["i-086e06769b6c67665","i-0477b6f25ad155290","i-0e6320273511d17dc"]

}

resource “aws_cloudwatch_dashboard” “ec2” {

dashboard_name = "ec2-test-dashboard"

count = length(var.targets)

dashboard_body = <<EOF
{
    "widgets": [
        {
            "type": "metric",
            "x": 0,
            "y": 0,
            "width": 17,
            "height": 8,
            "properties": {
                "metrics": [
                    ["AWS/EC2","CPUUtilization","InstanceId","${(var.targets[count.index])}"]            
                ],
                "title": "EC2 dashboard: CPUUtilization",
                "stat": "Average",
                "period": 300,
                "stacked": false,
                "view": "timeSeries",
                "region": "eu-west-1",
                "annotations": {
                    "horizontal": [
                        {
                            "label": "critical range",
                            "value": 10
                        }
                    ]
                },
                "legend": {
                    "position": "right"
                }
            }
        
        }

    ]
}
EOF

}