How convert a list into list of object in ansible

In my playbook I have a list like this

users:
  - readonly
  - write

and I need to translate it to a list of objects/dictionaries

userDict:
  - {'username': readonly, 'database': admin}
  - {'username': write, 'database': admin}

I know, I can do it with Jinja templates:

userDict: |
  {% set ret = [] %}
  {% for item in users %}
  {%   set _ = ret.append({'username': item, 'database': 'admin'}) %}
  {% endfor %}
  {{ ret }}

But I am looking for a shorter solution with filter, something like this:

userDict: "{{ users | map('map', 'username') | combine({'database': admin}) }}"

There are acutally two questions

• How to create a list of dicts from a list
• How to add an element to a list of dicts

A minimal example could look like

---
- hosts: localhost
  become: false
  gather_facts: false

  vars:

    users:
      - readonly
      - write

  tasks:

    - debug:
        msg: |
          {% set ret = [] %}
          {% for item in users %}
          {%   set _ = ret.append({'username': item, 'database': 'admin'}) %}
          {% endfor %}
          {{ ret }}

    - name: Create a new list
      debug:
        msg: "{{ item | combine( {'database': 'admin'} ) }}"
      loop: "{{ users | map('community.general.dict_kv', 'username') }}"
      loop_control:
        extended: true
        label: "{{ ansible_loop.index }}"

resulting into an output of

TASK [debug] *****************
ok: [localhost] =>
  msg:
  - database: admin
    username: readonly
  - database: admin
    username: write

TASK [Create a new list] *****
ok: [localhost] => (item=1) =>
  msg:
    database: admin
    username: readonly
ok: [localhost] => (item=2) =>
  msg:
    database: admin
    username: write

So finally one may end up with

    - name: Create a new list
      debug:
        msg: "{{ users | map('community.general.dict_kv', 'username') | map('combine', db_entry) }}"
      vars:
        db_entry: {'database': 'admin'}