I will definitely consider using my USB drive instead of the Windows Recovery tool now, it was just more convenient.
About my situation, I guess I'll have to format.. Again, annoying but yeah, what can I do else? I can't just keep having a corrupted Windows Defender as the only tool to protect me for malicious intents. At least I can say I tried to fix it before hand :')
When I did the "Reset my PC" I did not have to reformat anything, it worked without reformatting.
It was just a pain for the long time it took, but everything worked out fine. π€£
Why did you reset your computer if you did not have any issues before?
What about restoring an Image backup? Do you keep backups of your working systems?
Submit an FBH report with your problem if you want any investigation done by MS.