What can I do to fix and recover files on an SSD?

Out of the blue a few days ago my Dell notebook Win 11 with a NVME M.2 drive (with UEFI) crashed, with a boot issue. The PC would not boot to Windows, only to a blue screen saying my PC needed to be repaired. Over 2 full days I tried fixing the drive using for example many utilities such as bootrec /fixmbr etc etc etc and connecting a Win 11 bootable USB drive but nothing helped. In the blue recovery screen I was able to use the Command Line and was able to navigate to C:\ and could see all my folders and files. (And FYI I was able to use 'copy' to transfer a couple of important files to a USB

Question by UltraFusion on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.