Fuck this guy. Living out my dream ;'(
If we ignore the actual stress of a manager suddenly finding out and asking you to report what you have been doing. Probably still possible to bullshit long enough in a big company to recover a normal situation or find another job.
This is why you shouldn’t get rid of all your work. Keep a bit and make it immaculate. If they ask why you haven’t done more, just say “nobody asked me to.”
Problem with that approach is that they will argue that if you didn’t have enough work to do, you should have asked for more. OP knowingly slipped through the cracks to, so the argument of ‘I don’t have a line manager to give me any’ probably isn’t going to cut it as their work will argue that OP should’ve gone to HR to sort their responsibilities as soon as they were aware.