Can´t find a way to undelete files on ext4 disk [closed]

Per accident I shift+deleted a folder with subfolders from a 2nd disk on my machine (Ubuntu 24.04 / ext4 filesystem). I searched on how to un-delete the files but without success. This happenned about 24 hours ago.

Steps I took:

1. In order to preserve the disk, no new files have been copied ordeleted from this 2nd disk (/dev/sdc1).
2. Unmounted /dev/sdc1
3. Ran the extundelete command below, it shows no recoverable inodes
4. Prepared a rescatux live USB stick and ran testdisk, also didn´tfind anything to recover

Is there a way to recover the deleted files, or are they lost for good?

Output of the extundelete command:

xxx:~$ sudo extundelete --restore-all --after $(date -d "-30 hours" +%s) /dev/sdc1[sudo] password for xxx: Only show and process deleted entries if they are deleted on or after 1725723177 and before 9223372036854775807.NOTICE: Extended attributes are not restored.Loading filesystem metadata ... 15746 groups loaded.Loading journal descriptors ... 0 descriptors loaded.Searching for recoverable inodes in directory / ... 0 recoverable inodes found.Looking through the directory structure for deleted files ... 0 recoverable inodes still lost.No files were undeleted.

Thx!