i have succeeded in removing completely the "Windows Defender" and this solution survive reboots,
the method is fairly easy, but the implementation is a bit tedious,
you need to "destroy
" the app executables, in order to keep a rollback option i have only renamed them (and not deleted them),
in order to do that i have boot into safe mode
,
for every folder i took ownership on it (right click the folder -> properties -> security tab -> Advanced -> Change (next to the Owner label) and select your user, click apply to all subfolders and files, then add full access to your user)
now you can renamed these folders (i added a 111 prefix to all of them so they will appear at the top of the file list if i need them all in one place for rollback):
C:\Program Files\Windows Defender
C:\Program Files (x86)\Windows Defender
and renamed allot of folders and files inside:
C:\ProgramData\Microsoft\Windows Defender
because even safe mode did not allow me to rename the folder and several files inside it (since the service is active), so i renamed allot of them (especially dll, exe and bin files so the service wont have enough to work with in the next boot),
and then i rebooted into safe mode again, that time the defender did not work anymore and i was able to rename the folder:
C:\ProgramData\Microsoft\Windows Defender
that's it, reboot again into normal mode and you will no longer see the Windows Defender in the Windows Security Center