Please let me describe in short what happened.
I have a Host running NAS Software OpenMediaVault6 on a Virtual Machine. In OMV6 it is defined to store the data on a separate NVME disk. File Format is EXT4. The drive is not encrypted. I did never use any partitions just the full NVME.
After restarting the host the storage NVME was not visible. I went to OMV6 and without thinking wanted to mount the NVME storage disk. However I did not click on Mount but on Create and created a new EXT4 over the old one.
All my data on the NVME are not accessible any more. I ran Quicksearch via Testdisk and it only finds one partition (the new one which I created via OMV6 accidentally). In this partition I can see two folders and one file.
With Deepsearch I can find a second partition. Please see image below:

Problem here is that I can only access the second partition which gives the same folder/file result as the Quicksearch. If I open the first partition (which I assume is the one I am looking for) I get the following error: Can't open filesystem. Filesystem seems damaged.

As said the partition has no boot etc. just plain data.
Is this the chapter I want to look at? 7.7 TestDisk: repairing ext2/3/4 filesystem superblock
Because in fact I have a working EXT4 filesystem. I just want the old one.
Am I missing any info so far? Thank you