This line
SFC /SCANNOW /OFFBOOTDIR=C:\ /OFFWINDIR=C:\Windows
should have been entered in the Recovery Environment > Command Prompt (Start computer > tap F8 > select Repair Your Computer > Recovery Environment > Command Prompt). Do not enter it in Safe Mode as it will not work there.
You are correct in the spaces; there should be a space before every / . And we are on almost opposite sides of the planet (I’m in BC, Canada) but I will try and keep up.
EDIT:
Did you mean this command (in Safe Mode) dism.exe /image:C:\ /cleanup-image /revertpendingactions
or
this one SFC /SCANNOW /OFFBOOTDIR=C:\ /OFFWINDIR=C:\Windows ?
Now SFC is working? Yeah; let’s see what happens there.