Broken MBR / GRUB can't boot on Qubes OS partition

The issue

After are bad installation of a linux live usb ( which I believe have re-written the MBR of my laptop harddrive instead of the one of the thumb drive ) I can’t boot on my Qubes OS partition any more. I have a dual boot with three main partitions:
one for windows, one for data storage ( ext4 ) and one for qubes OS ( see picture )

What I have done so far

My first attempt was to use boot-repair automatic repair → the computer was booting on windows.
Then I used boot-repair to manually set the boot flag to nvme0np5 which I believe is the grub partition , but it didn’t worked.

What are my options to fix this issue ? I can provide more information if needed

You can try to mount and chroot into your Qubes OS from some Live USB and reinstall GRUB like this: