I REALLY messed up and am not sure how to proceed...
I have a dev workstation with a 512GB Samsung SSD that multi-boots Windows 10, OpenSuse, and Ubuntu. I was making space for one more testing distro when I blasted everything with a bad format command. After creating the new partition successfully, I ran the following incomplete command by not designating the specific partition to format: mkfs.ext4 /dev/nvme0n1 (should have been /dev/nvme0n1p8). Now there is no partition table and one whole disk ext4file system where I used to have a partition table with the happy little partitions.
I've tried to use TestDisk (via SystemRescueCD) multiple times to recover the table and partition information, but no joy. TestDisk states that there is no partition table and any attempts to scan (normal or deep looking for GPT) only find the new invalid file system and gives nothing to recover.
The only thing I have done is reboot the workstation once into SystemRescueCD in order to run TestDisk and do a few scans. At this point, I'm stumped with this specific situation and quite terrified to do anything so I thought I would reach out and see if anyone could assist. TestDisk is just awesome and has always been able to bail me out, but then again, I've never messed up this badly!

Thanks much!