Well that sounds more like a mechanical failure if one TR blade hasn't been recovered yet.
That's a bold statement crab.
Just because a blade is missing doesn't mean it came off before impact. The fact that all blades came off would suggest that power was still being applied at impact.
Let's see what the MPFDR says. And the vibration monitoring system, if it was active (the accident aircraft does not have HUMS but rather VXP).