I had a smaller M2 SSD which I've cloned with clonezilla to a 1 tb M2 SSD.This contained a dual boot with Windows 10 and Debian.
At first it didn't boot Windows or Debian.
After some restarting I used the Windows repair function to at least get into Windows.
Now Debian (Grub?) is still broken.
I used a live Debian USB drive to try and run Bootrepair but this didn't work.
I do have the pastebin here. If I'm not mistaken I do see a Linux filesystem on nvme0n1p4 but I couldn't mount it. I got the error message "wrong fs type, bad option, bad superblock".
Now I'm stuck. Please help me boot into my beloved Debian once again so I can leave Windows behind.