How to pass argument from tfvars.tf file to the templatefile function of resource "aws_instance" user_data>

I'm tired to utilize terraform as used on this website https://www.middlewareinventory.com/blog/terraform-create-multiple-ec2-different-config/ Terraform Create Multiple EC2 with different Configs – for_each and count together. Instead of using the HereDocument, I'm trying to use The Terraform templatefile function. However, I received the following errors:

Error: Invalid function argument
on main.tf line 36, in resource "aws_instance" "web":
36:  user_data = templatefile(${each.value.appl_name}","${each.value.appl_version}")
    each.value.appl_name is tuple with 1 element
    
    Invalid value for "path" parameter: string required. 
    ...
    ...
    ...

I've included the terraform config files below

Please advise.

    #dev.tfvars
    configuration = [
      {
        "application_name" : "GritfyApp-dev",
        "ami" : "ami-09e67e426f25ce0d7",
        "no_of_instances" : "2",
        "instance_type" : "t2.medium",
        "subnet_id" : "subnet-0f4f294d8404946eb",
        "vpc_security_group_ids" : ["sg-0d15a4cac0567478c","sg-0d8749c35f7439f3e"],
        "appl_version" : [{ appl_1_version = "1.0" }],
        "appl_name"     : [/app_dir/appl_1_script.tpl"]
      },
      {
        "application_name" : "GrityWeb-dev",
        "ami" : "ami-0747bdcabd34c712a",
        "instance_type" : "t2.micro",
        "no_of_instances" : "1"
        "subnet_id" : "subnet-0f4f294d8404946eb",
        "vpc_security_group_ids" : ["sg-0d15a4cac0567478c"],
        "appl_version" : [{ appl_2_version = "5.0" }],
        "appl_name"     : [/app_dir/appl_2_script.tpl"]
      },
      {
        "application_name" : "OpsGrit-dev",
        "ami" : "ami-0747bdcabd34c712a",
        "instance_type" : "t3.micro",
        "no_of_instances" : "3",
        "subnet_id" : "subnet-0f4f294d8404946eb",
        "vpc_security_group_ids" : ["sg-0d15a4cac0567478c"],
        "appl_version" : [{ appl_2_version = "5.1.0" }],
        "appl_name"     : [/app_dir/fixit_script.tpl"]  
      }
      
    ]

    #main.tf
    provider "aws" {
      region = "us-east-1"
      profile = "personal"
    
    }
    
    locals {
      serverconfig = [
        for srv in var.configuration : [
          for i in range(1, srv.no_of_instances+1) : {
            instance_name = "${srv.application_name}-${i}"
            instance_type = srv.instance_type
            subnet_id   = srv.subnet_id
            ami = srv.ami
            security_groups = srv.vpc_security_group_ids
            appl_version = "${srv.appl_version}"
            appl_name = "${srv.appl_name}"
          }
        ]
      ]
    }
    
    // We need to Flatten it before using it
    locals {
      instances = flatten(local.serverconfig)
    }
    
    resource "aws_instance" "web" {
    
      for_each = {for server in local.instances: server.instance_name =>  server}
      
      ami           = each.value.ami
      instance_type = each.value.instance_type
      vpc_security_group_ids = each.value.security_groups
      user_data = templatefile(${each.value.appl_name}","${each.value.appl_version}")
      subnet_id = each.value.subnet_id
      tags = {
        Name = "${each.value.instance_name}"
      }
    }
    
    output "instances" {
      value       = "${aws_instance.web}"
      description = "All Machine details"
    }