This is my current setup in my cloudformation stack arch yaml

UserData: !Base64
            Fn::Join:
               - ''
               - ["#!/bin/bash -xe",
                  " n echo "export ENV_PROFILE=",{ "Fn::Sub": "${Environment}" },"" >> /etc/profile.d/app-profile-vars.sh",
                  " n source /etc/profile.d/app-profile-vars.sh",
                  " n sudo su",
                  " n sudo yum install -y chrony",
                  " n sudo service chronyd restart",
                  " n sudo timedatectl set-timezone America/Chicago",
                  " n sudo chkconfig chronyd on",
                  " n sudo yum install -y perl-Switch perl-DateTime perl-Sys-Syslog perl-LWP-Protocol-https perl-Digest-SHA.x86_64",
                  " n cd /home/ec2-user",
                  " n curl https://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.2.zip -O",
                  " n unzip CloudWatchMonitoringScripts-1.2.2.zip",
                  " n aws s3 cp s3://scorecardprodcodedeploybucket/cloudwatch/config.json /opt/aws/amazon-cloudwatch-agent/bin/config.json",
                  " n /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c file:/opt/aws/amazon-cloudwatch-agent/bin/config.json -s",
                  #"n /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -m ec2 -a statusn",
                  " n chown root:root aws-scripts-mon",
                  " n echo "*/5 * * * * root /home/ec2-user/aws-scripts-mon/mon-put-instance-data.pl --mem-used-incl-cache-buff --mem-util --disk-space-used --disk-space-avail --disk-space-util --disk-path=/ --auto-scaling=only --from-cron" >> /etc/crontab",
                  " n aws s3 cp s3://appdynamicscorecardadbp/AppServerAgent-1.8-22.1.0.33445.zip /opt/appdynamics/java-agent/java-AppServerAgent-1.8-22.1.0.33445.zip  --sse AES256 --region us-east-1",
                  " n cd /opt/appdynamics/java-agent",
                  " n unzip java-AppServerAgent-1.8-22.1.0.33445.zip",
                  " n aws s3 cp s3://appdynamicscorecardadbp/scorecard/controller-info.xml /opt/appdynamics/java-agent/conf/controller-info.xml  --sse AES256 --region us-east-1"
               ]

I have the var file for the parameter in JSON format

Can I take the whole userdata in the parameter like this

{
        "ParameterKey": "UserData",
        "ParameterValue": "#!/bin/bash -xe",
        " n echo "export ENV_PROFILE=",{ "Fn::Sub": "${Environment}" },"" >> /etc/profile.d/app-profile-vars.sh",
    " n source /etc/profile.d/app-profile-vars.sh",
    " n sudo su",
    " n sudo yum install -y chrony",
    " n sudo service chronyd restart",
    " n sudo timedatectl set-timezone America/Chicago",
    " n sudo chkconfig chronyd on",
    " n sudo yum install -y perl-Switch perl-DateTime perl-Sys-Syslog perl-LWP-Protocol-https perl-Digest-SHA.x86_64",
    " n cd /home/ec2-user",
    " n curl https://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.2.zip -O",
    " n unzip CloudWatchMonitoringScripts-1.2.2.zip",
    " n aws s3 cp s3://scorecardprodcodedeploybucket/cloudwatch/config.json /opt/aws/amazon-cloudwatch-agent/bin/config.json",
    " n /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c file:/opt/aws/amazon-cloudwatch-agent/bin/config.json -s",
    "n #/opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -m ec2 -a statusn",
    " n chown root:root aws-scripts-mon",
    " n echo "*/5 * * * * root /home/ec2-user/aws-scripts-mon/mon-put-instance-data.pl --mem-used-incl-cache-buff --mem-util --disk-space-used --disk-space-avail --disk-space-util --disk-path=/ --auto-scaling=only --from-cron" >> /etc/crontab",
    " n aws s3 cp s3://appdynamicscorecardadbp/AppServerAgent-1.8-22.1.0.33445.zip /opt/appdynamics/java-agent/java-AppServerAgent-1.8-22.1.0.33445.zip  --sse AES256 --region us-east-1",
    " n cd /opt/appdynamics/java-agent",
    " n unzip java-AppServerAgent-1.8-22.1.0.33445.zip",
    " n aws s3 cp s3://appdynamicscorecardadbp/scorecard/controller-info.xml /opt/appdynamics/java-agent/conf/controller-info.xml  --sse AES256 --region us-east-1",

    }

And refer the parameter something like this

        UserData: !Base64
            Fn::Join:
               - ''
               - ["$UserData"]

As I am taking for other parameters

ImageId: !Sub "${AmiId}"