Issue:
Problem:

Reason :
NVMe SSD isn't in bootlist option anymore. Could be related to an old bios revision or Damaged Motherboard
Solution:
1) Go in Bios Setup pressing F12 at boot

2) Boot Configuration

3) Add a boot option :

4) Select NVme disk (PC SSD)

5) Select EFI

6) Select EFI\debian\shim64.efi
6) Put a name for this entry

7) Check it, pushing this entry as first in boot sequence.

Apply Saves and reboot.