[Bug]: Compress zip files

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• Nextcloud Server is running on 64bit capable CPU, PHP and OS.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When downloading multiple files or a folder, the zip file has no compression on it.

If a folder in NC shows as 120MB in size, the output/downloaded zip will be roughly the same size.
Unpacking the files and then repacking them with let say 7z (in my case) reduced the file by almost 40% (in my case 78MB).

Steps to reproduce

1. Select multiple files/folder
2. Download the file
3. Downloaded zip has no compression enabled

File downloaded directly from NC:

Same content after 7z compression:

Expected behavior

Should we have compression enabled, so the resulting file is smaller?

I understand that there would be a penality for the system compressing files, but can't judge if it will outweigh the gains of transfer time.

Installation method

Community Manual installation with Archive

Nextcloud Server version

25

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.1

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

Enabled:
  - activity: 2.17.0
  - announcementcenter: 6.6.1
  - cloud_federation_api: 1.8.0
  - comments: 1.15.0
  - contactsinteraction: 1.6.0
  - dashboard: 7.5.0
  - dav: 1.24.0
  - federatedfilesharing: 1.15.0
  - federation: 1.15.0
  - files: 1.20.1
  - files_accesscontrol: 1.15.1
  - files_automatedtagging: 1.15.3
  - files_external: 1.17.0
  - files_pdfviewer: 2.6.0
  - files_rightclick: 1.4.0
  - files_scripts: 2.2.1
  - files_sharing: 1.17.0
  - files_snapshots: 1.0.6
  - files_trackdownloads: 1.11.0
  - files_trashbin: 1.15.0
  - files_versions: 1.18.0
  - fileslibreofficeedit: 1.1.0
  - flow_notifications: 1.5.0
  - groupfolders: 13.1.3
  - logreader: 2.10.0
  - lookup_server_connector: 1.13.0
  - nextcloud_announcements: 1.14.0
  - notifications: 2.13.1
  - oauth2: 1.13.0
  - password_policy: 1.15.0
  - privacy: 1.9.0
  - provisioning_api: 1.15.0
  - recommendations: 1.4.0
  - related_resources: 1.0.4
  - richdocuments: 7.1.4
  - richdocumentscode: 22.5.1301
  - serverinfo: 1.15.0
  - settings: 1.7.0
  - sharebymail: 1.15.0
  - spreed: 15.0.5
  - survey_client: 1.13.0
  - suspicious_login: 4.3.0
  - systemtags: 1.15.0
  - tasks: 0.15.0
  - terms_of_service: 2.2.0
  - text: 3.6.0
  - theming: 2.0.1
  - twofactor_backupcodes: 1.14.0
  - updatenotification: 1.15.0
  - user_ldap: 1.15.0
  - user_status: 1.5.0
  - viewer: 1.9.0
  - weather_status: 1.5.0
  - workflowengine: 2.7.0

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response

No files or tests are named in the issue. Start by tracing the server path used when downloading multiple files or a folder and identify how the ZIP archive is created; check whether compression is intentionally disabled. Done means downloads use the agreed compression behavior without breaking archive generation, with coverage for multi-file and folder downloads.