Ansible reject with search/regex

I try to manipulate the ouptut of following powershell command:

Get-CimInstance -ClassName Win32_UserProfile | Select-Object -ExpandProperty LocalPath

Which could look like this:

[
  "C:\\Users\\LocalUser",
  "C:\\Users\\LocalUser.001",
  "C:\\Users\\Admin",
  "C:\\Windows\\ServiceProfiles\\NetworkService",
  "C:\\Windows\\ServiceProfiles\\LocalService",
  "C:\\Windows\\system32\\config\\systemprofile"
]

My goal is to reject the profiles, like Admin and them under Windows path.

My approach so far looks like this:

- hosts: windows10
  gather_facts: false

  tasks:
    - name: Get a list of all user profiles
      ansible.windows.win_powershell:
        script: |
          Get-CimInstance -ClassName Win32_UserProfile |
          Select-Object -ExpandProperty LocalPath
      register: all_user_profiles
      changed_when: false

    - name: Filter profiles for deletion
      set_fact:
        profiles_to_delete: >-
          {{ all_user_profiles.output |
             reject('search', '\\\\Users\\\\(' + (keep_users | join("|")) + ')') |
             list }}
      vars:
        keep_users:
          - Admin
      

    - debug:
        var: profiles_to_delete

The Expected result from the last debug:

[
  "C:\\Users\\LocalUser",
  "C:\\Users\\LocalUser.001",
  "C:\\Windows\\ServiceProfiles\\NetworkService",
  "C:\\Windows\\ServiceProfiles\\LocalService",
  "C:\\Windows\\system32\\config\\systemprofile"
]

But instead it still includes the Admin line, from above.

I tested also the following based on @β.εηοιτ.βε gist from the comments:

- hosts: localhost
  gather_facts: false

  tasks:
    - name: Filter profiles for deletion
      set_fact:
        profiles_to_delete: >-
          {{ all_user_profiles.output |
             reject('search', '\\\\Users\\\\(' + (keep_users | join("|")) + ')') |
             list }}
      vars:
        keep_users:
          - Admin
        all_user_profiles:
          output:
            - C:\\Users\\LocalUser
            - C:\\Users\\LocalUser.001
            - C:\\Users\\Admin
            - C:\\Windows\\ServiceProfiles\\NetworkService
            - C:\\Windows\\ServiceProfiles\\LocalService
            - C:\\Windows\\system32\\config\\systemprofile

    - debug:
        var: profiles_to_delete

And here it works fine as expected.

So I compared the two lists and came to the conclusion, that the issue is originating from the difference, that the content of the shell output is quoted and the content of the hardcoded variable is not.

As soon as I update the hardcoded variable, I get the same unwanted result as my MWE creates:

all_user_profiles:
  output:
    - "C:\\Users\\LocalUser"
    - "C:\\Users\\LocalUser.001"
    - "C:\\Users\\Admin"
    - "C:\\Windows\\ServiceProfiles\\NetworkService"
    - "C:\\Windows\\ServiceProfiles\\LocalService"
    - "C:\\Windows\\system32\\config\\systemprofile"

So, why does the search not work if the values are quoted?

Since all_user_profile.output just seems to be list and you like to remove (reject) an item from that list, a minimal example playbook

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

  vars:

    all_user_profile:
      output: [
        "C:\\Users\\LocalUser",
        "C:\\Users\\LocalUser.001",
        "C:\\Users\\Admin",
        "C:\\Windows\\ServiceProfiles\\NetworkService",
        "C:\\Windows\\ServiceProfiles\\LocalService",
        "C:\\Windows\\system32\\config\\systemprofile"
      ]

  tasks:

    - name: Profiles to delete
      debug:
        msg: "{{ all_user_profile.output | reject('search', user) | list }}"
      vars:
        user: Admin

will result into an output of

TASK [Profiles to delete] *******************
ok: [localhost] =>
  msg:
  - C:\Users\LocalUser
  - C:\Users\LocalUser.001
  - C:\Windows\ServiceProfiles\NetworkService
  - C:\Windows\ServiceProfiles\LocalService
  - C:\Windows\system32\config\systemprofile

It is also possible to specify the path in more detail, see in example

    - name: Profiles to delete
      debug:
        msg: "{{ all_user_profile.output | reject('search', keep) | list }}"
      vars:
        keep: Users\\Admin