Note that both of the above commands just rewrite the executable part of MBR/VBR, other parts are untouched e.g. Partition Table in MBR. Like Partition Table in MBR describes partition layout, BIOS Parameter Block in NTFS VBR describes filesystem layout. /FixBoot cannot fix problems in BPB.
For instance if you replace the Windows Active Partition, or move the installation to another disk so that the starting sector number of the partition changes, Windows won't boot, even if you fix MBR/VBR and recreate/fix BCD entries (using bcdboot/bcdedit, which is also required if the disk identifier/signature changes because that's hard-coded in BCD store entries). In one of the BPB fields the number of first partition sector is hard-coded, which needs to be fixed. You can see details here.