'include_vars' doesn't find the vars file

[dulh...@mailbox.org]

I want to include a defaults, or variable file in the /defaults/main.yml of a role I am playing
Upon execution I am getting "the defaults/main.yml file for role 'postgres_disable' must contain a dictionary of variables"

====== DETAILED ERROR ============================================================
ansible-playbook [core 2.12.2]
config file = /home/gwagner/repos/ansible/open_source/postgres_upgrade/ansible.cfg
configured module search path = ['/home/gwagner/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python3.8/site-packages/ansible
ansible collection location = /home/gwagner/.ansible/collections:/usr/share/ansible/collections
executable location = /usr/bin/ansible-playbook
python version = 3.8.12 (default, Sep 16 2021, 10:46:05) [GCC 8.5.0 20210514 (Red Hat 8.5.0-3)]
jinja version = 2.10.3
libyaml = True
Using /home/gwagner/repos/ansible/open_source/postgres_upgrade/ansible.cfg as config file
host_list declined parsing /etc/ansible/hosts as it did not pass its verify_file() method
script declined parsing /etc/ansible/hosts as it did not pass its verify_file() method
auto declined parsing /etc/ansible/hosts as it did not pass its verify_file() method
Parsed /etc/ansible/hosts inventory source with ini plugin
[WARNING]: provided hosts list is empty, only localhost is available. Note that the implicit localhost does not match 'all'
ERROR! The defaults/main.yml file for role 'postgres_disable' must contain a dictionary of variables
==================================================================================


I tried all 3 variants of addressing the file in the TASK below seprately. Each of them throws the same error

===== my TASK ====================================================================
- name: include defaults file
ansible.builtin.include_vars:
file: "{{ item }}"
loop:
- ../vars/pg_disable_defaults.yml
- /home/gwagner/repos/ansible/open_source/postgres_upgrade/roles/postgres_disable/vars/pg_disable_defaults.yml
- pg_disable_defaults.yml
==================================================================================

===== my FOLDER STRUCTURE ========================================================

roles/postgres_disable/
├── defaults
│   └── main.yml
├── handlers
│   └── main.yml
├── meta
│   └── main.yml
├── README.md
├── tasks
│   ├── main.yml
│   └── postgres_disable.yml
├── tests
│   ├── inventory
│   └── test.yml
└── vars
├── main.yml
└── pg_disable_defaults.yml
==================================================================================

the pg_disable_defaults.yml works as soon I move it to ~/defaults/main.yml, so the file itself does not appear to be the source of bad here.

Seems I am fundamentally getting something wrong here ... what is it?

Maybe the idea of a starting point in 'role_name/defaults/main.yml'?