The short version:
Blood oxygen levels were falling into "should be dead" levels never really seen before (even though they were otherwise alert and fine and had no other hypoxia indicators), which caused doctors to panic about pneumonia and not being able to breathe, and put people on ventilators prematurely. However, it wasn't really having an effect, so the ventilators kept getting turned up to their maximum setting, which puts too much pressure on the lungs and causes additional permanent damage. In most people this caused a turn for the worse instead of recovery.
Their death rate in April was the same as the peak of the second wave in December.
https://time.com/5107984/hospitals-handling-burden-flu-patie...
No, they aren't. Your article is talking about the 2017-2018 flu season, which was an anomaly when it came to hospitalizations and deaths. Both hospitalizations and deaths that season were about double what they normally are[1]. About 61k people died in the US during that flu season, where about 20k-35k normally die. There were 810k hospitalizations, while hospitalizations usually fluctuate between 250k-500k.
