Target team folders without namespace

It looks like you're trying to operate on files inside the "team space". In order to access the team space, you do need to use the "Dropbox-API-Path-Root" header. It's not possible to access the contents of the team space without using the "Dropbox-API-Path-Root" header, but there are different ways to use the "Dropbox-API-Path-Root" header.

For example, you can use the "root" mode (instead of the "namespace_id" mode like you have in your sample) to access the root namespace for an account, which would be the team space for an account on a team using a team space configuration.

You can get the root_namespace_id for an account by calling /2/users/get_current_account for that account, and then plug that in to the "Dropbox-API-Path-Root" header on subsequent calls. You can find more information on how to use this functionality in the Team Files Guide.

When doing so, you should then supply the path value relative to that root. So for your example, that would look like:

curl -X POST https://api.dropboxapi.com/2/files/lock_file_batch \
    -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
    -H "Content-Type: application/json" \
    -H "Dropbox-API-Select-User: YOUR_USER_ID" \
    -H "Dropbox-API-Path-Root: {\".tag\": \"root\", \"root\": \"ROOT_NAMESPACE_ID\"}" \
    -d '{
          "entries": [
              {
                  "path": "/Soft launch/_2024-06-17_Dropbox-Tests/2024-06-17_Dropbox-Test Leerzeichen.indd"
              }
          ]
       }'