https://stackoverflow.com/questions/76247218/building-inventory-list-with-different-sets-of-users?noredirect=1#comment134459224_76247218

gistfile1.txt

$ cat inventory.yml
---
cloud1:
  vars:
    ansible_user: specific_service_user
  hosts:
    host1:
    host2:
cloud2:
  vars:
    ansible_user: admin
  host:
    host3:
    host4:
cloud3:
  vars:
    ansible_user: root
  hosts:
    host5:
    host6:
    
$ cat dummy_example.yml
---
- name: An entire play as root
  hosts: all
  become: true

  tasks:
    - name: install a package
      package:
        name: vim
        state: present

- name: An entire play as arbitrary user
  hosts: all
  become_user: postgres
  become: true
  
  tasks:
    - name: Do something as postgres
      lineinfile:
        dest: /var/lib/postgres/{{ postgres_version }}/postgres.conf
        line: "# a dummy line"
        
- name Specific tasks as different users
  hosts: all
  
  tasks:
    - name: run as connection user
      shell: id -a
      register: as_normal
      
    - name: run as root
      become: true
      shell: id -a
      register: as_root
      
    - name: run as someone
      become_user: someone
      become: true
      shell: id -a
      register as_someone
      
    - name: show all resulst from above
      debug:
        var: "{{ item }}"
      loop:
        - as_normal
        - as_root
        - as_someone