Ansible: linked second playbook is not able to run a script for variables passed from multiple hosts from the first playbook

I am using 2 playbooks linked, there details mentioned below.

playbook1: collect raw data from multiple machines

- hosts: target_1
  gather_facts: false


  tasks:
   - name: Register a new value
     shell: df -h|awk '{gsub("%","|");print $5 $6}'
     register: PLAY1VAR

   - debug: msg="{{PLAY1VAR.stdout}}"

   - name: Register a new value
     shell: hostname
     register: PLAY2VAR

   - debug: msg="{{PLAY2VAR.stdout}}"

   - name: Register dummy host with variable
     add_host:
       name: "DUMMY_HOST"
       PLAY1VAR_NEW: " {{ PLAY1VAR.stdout }}"

   - name: Register dummy host with variable
     add_host:
       name: "DUMMY_HOST_1"
       PLAY2VAR_NEW: " {{ PLAY2VAR.stdout }}"
- hosts: target_2
  gather_facts: false


  tasks:
   - name: Register a new value

playbook2:parse data using python script

- hosts: localhost
  gather_facts: false

  tasks:
   - name: Echo the output - PLAY1 variable vaule
     command: python3 /opt/diskspace_watcher/watcher.py '{{hostvars['DUMMY_HOST']['PLAY1VAR_NEW']}}' '{{hostvars['DUMMY_HOST_1']['PLAY2VAR_NEW']}}'
     register: PLAY2_RESULTS

   - debug: msg="{{PLAY2_RESULTS.stdout}}"

I am passing couple of variables from the first playbook to another, when I am running this for just one host it is working as expected but when trying to run for multiple host it is unable to pass the arguments for all the host mentioned in the inventory file and is just picking up one variable for a particular host.

I am looking for a way to get this executed. Any help/idea is appreciated!!