Assume 3 roles:

• aix_setup
• ppc64le_setup
• x86_64_setup

site.yml
roles/
├── aix_setup/
├── ppc64le_setup/
└── x86_64_setup/

# ansible-galaxy init roles/aix_setup
# ansible-galaxy init roles/ppc64le_setup
# ansible-galaxy init roles/x86_64_setup

roles/
├── aix_setup/
│   ├── defaults/
│   │   └── main.yml
│   ├── files/
│   ├── handlers/
│   │   └── main.yml
│   ├── meta/
│   │   └── main.yml
│   ├── tasks/
│   │   └── main.yml
│   ├── templates/
│   ├── tests/
│   │   ├── inventory
│   │   └── test.yml
│   └── vars/
│       └── main.yml

Example main.yml

# cat roles/ppc64le_setup/tasks/main.yml
---
- name: Print ppc64le architecture and OS
  debug:
    msg: "Running setup role on {{ inventory_hostname }}, OS: {{ ansible_system }}, Arch: {{ ansible_architecture }}"

# cat conditional_roles.yml
---
- name: Run role based on system architecture and OS
  hosts: all
  become: yes
  gather_facts: yes

  pre_tasks:
    - name: Get AIX version if applicable
      ansible.builtin.shell: oslevel
      when: ansible_system == "AIX"
      register: aix_version
      changed_when: false

  roles:

    - role: aix_setup
      when:
        - ansible_system == "AIX"
        - "'7.2' in aix_version.stdout or '7.3' in aix_version.stdout"

    - role: ppc64le_setup
      when:
        - ansible_architecture == "ppc64le"
        - ansible_system != "AIX"

    - role: x86_64_setup
      when:
        - ansible_architecture == "x86_64"
        - ansible_system != "AIX"

Also useful facts:

"ansible_os_family": "AIX",
"ansible_distribution": "AIX",
"ansible_distribution_major_version": "7",
"ansible_distribution_release": "2",
"ansible_distribution_version": "7.2",
"ansible_architecture": "chrp",
"ansible_system": "AIX"

"ansible_os_family": "RedHat",
"ansible_distribution": "openSUSE Leap",
"ansible_distribution_file_variety": "SUSE",
"ansible_distribution_major_version": "15",
"ansible_distribution_release": "1",
"ansible_distribution_version": "15.1",
"ansible_architecture": "x86_64",
"ansible_system": "Linux"

or “ansible_architecture”: “ppc64le”,

# cat pretask.yml
---
- name: Set Python interpreter based on AIX version
  hosts: aix_hosts
  gather_facts: false  # we'll do manual version check
  become: yes

  pre_tasks:

    - name: Get AIX version
      ansible.builtin.shell: oslevel
      register: aix_version
      changed_when: false

    - name: Set Python interpreter for AIX 7.2
      ansible.builtin.set_fact:
        ansible_python_interpreter: "/opt/freeware/bin/python3"
      when: "'7.2' in aix_version.stdout"

    - name: Set Python interpreter for AIX 7.3
      ansible.builtin.set_fact:
        ansible_python_interpreter: "/opt/freeware/bin/python3_73"
      when: "'7.3' in aix_version.stdout"

  tasks:
    - name: Debug current interpreter
      ansible.builtin.debug:
        msg: "Using interpreter: {{ ansible_python_interpreter }}"

    # You can continue here with other tasks

# cat inventory.ini
[aix_hosts]
aixserver1 ansible_user=root ansible_connection=ssh ansible_python_interpreter=/opt/freeware/bin/python3

# cat lv_config.json
[
  {
    "vgname": "datavg",
    "lvname": "lv_data",
    "mount_point": "/data",
    "size": "2G"
    "type": "jfs2"
  },
  {
    "vgname": "appvg",
    "lvname": "lv_app",
    "mount_point": "/app",
    "size": "5G"
    "type": "jfs2"
  }
]

Create filesystems

# cat create_aix_lvs.yml
---
- name: Create Logical Volumes and Filesystems on AIX
  hosts: aix_hosts
  become: yes
  vars_files:
    - lv_config.json

  tasks:

    - name: Create logical volume
      ansible.builtin.shell: |
        mklv -t {{ item.type }} -y {{ item.lvname }} {{ item.vgname }} {{ item.size }}
      args:
        creates: "/dev/{{ item.lvname }}"
      loop: "{{ lv_config }}"

    - name: Create file system
      ansible.builtin.shell: |
        crfs -v {{ item.type }} -d {{ item.lvname }} -m {{ item.mount_point }} -A yes
      args:
        creates: "{{ item.mount_point }}"
      loop: "{{ lv_config }}"

    - name: Create mount point directory
      ansible.builtin.file:
        path: "{{ item.mount_point }}"
        state: directory
        mode: '0755'
      loop: "{{ lv_config }}"

    - name: Mount filesystem
      ansible.builtin.shell: |
        mount {{ item.mount_point }}
      loop: "{{ lv_config }}"

    - name: Ensure filesystem is in /etc/filesystems (automount)
      ansible.builtin.shell: |
        chfs -A yes {{ item.mount_point }}
      loop: "{{ lv_config }}"

Extend filesystems if smaller than desired

# cat extend_aix_lvs.yml
---
- name: Extend filesystems on AIX if current size is smaller
  hosts: aix_hosts
  become: yes
  vars_files:
    - lv_config.json

  tasks:
    - name: Get current size of filesystem
      ansible.builtin.shell: |
        lsfs {{ item.mount_point }} | awk 'NR>1 {print $3}'
      register: current_fs_size
      changed_when: false
      loop: "{{ lv_config }}"
      loop_control:
        label: "{{ item.mount_point }}"
      delegate_to: localhost

    - name: Set fact with comparison results
      ansible.builtin.set_fact:
        fs_resize_list: >-
          {{
            fs_resize_list | default([]) +
            [{
              'mount_point': item.1.mount_point,
              'lvname': item.1.lvname,
              'vgname': item.1.vgname,
              'current_size': (item.0.stdout | trim),
              'desired_size': item.1.size
            }] if (item.0.stdout | trim is version(item.1.size, '<')) else fs_resize_list | default([])
          }}
      loop: "{{ zip(current_fs_size.results, lv_config) }}"
      loop_control:
        label: "{{ item.1.mount_point }}"

    - name: Extend filesystem only if current size is less than desired
      ansible.builtin.shell: |
        chfs -a size={{ item.desired_size }} {{ item.mount_point }}
      loop: "{{ fs_resize_list }}"
      when: fs_resize_list | length > 0

Note

AIX lsfs returns sizes in 512-byte blocks. So 4194304 blocks = 2G. You may need a helper function to normalize that if you want more accuracy.

You could replace size parsing with something like:
lsfs /data | awk 'NR>1 {printf "%.0fG\n", $3*512/1024/1024/1024}'