In a very similar case (moved and enlarged partitions, so Windows system/
C: partition has been moved – which GParted explicitly warns about), I also had a non-bootable Windows with grub.
Symptom: Had a Windows 10 blue error screen directly after choosing Windows 10 in the grub boot menu with some cryptic error code, which shows not much information. It says I should press F8 for troubleshooting or Enter to retry, but F8 just shows the same error.
The problem other solutions tries have when you have a working grub you may not want to break that. As such, e.g. do not overwrite the MBR (breaks MBR and requires grub reinstall then) or overwrite the boot sector.
Also, automatically fixing via Windows 10 boot troubleshooting tool did not work.
Solution: Boot a Windows 10 installation media (GParted explains how to get it, direct link for Windows 10) and rebuild the Boot Configuration Data (BCD) store using the
cmd.exe/command line Windows 10 from thinstallation media:
IMHO the Microsoft doc linked from GParted is too cumbersome, and I suggest to refer to these detailed instructions by Ventoy.
This was the only command needed.
PS: In my case I installed the Windows 10 installation media via ventoy to have other rescue ISOs next to it, which worked well.
(Cross-posted from a similar question)