You can die on the order of hours to days not of high blood sugar per se, but of the low insulin causing diabetic ketoacidosis parent comment mentions.

It would be odd for a faulty sensor to cause an otherwise bad day into dka and death though. The sensor would need to be wildly off for hours and the user to not notice. Insulin delivery would need to be paused or greatly reduced for many hours. There are additional therapies like SGLT-2 that could make this more likely but they usually aren’t used with T1D precisely because they break the normally very strong correlation between inadequate insulin levels (leading to dka) and high blood glucose.

Even though I can’t think of an easy way for a false low(s) to turn into lethal DKA, that doesn’t mean it didn’t happen. Abbott sells a lot of CGMs. It could have been a contributing factor to several deaths even if the fault would almost always not be a significant issue.