Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
The machine shuts down by itself after a few minutes of use, probably because of overheat. It smells warm/overheated after vacuuming only a short while (half a normal room). I have never seen anything like it in my 49 years!
If the dust container and filters are not cleaned on a regular basis, the vacuum cleaner may overheat, which will cause the thermal cut-out device to activate due to restricted flow of air around the unit. If this happens, unplug it from the mains power suppy, then proceed to empty the dust container and clean all of the filters. Refer to the instruction manual for guidance.