Since less water would increase the detergent concentration, I was wondering if the opposite was the case. My family's old washer filled up the entire tub with water, so any detergent (and any pathogen, to be fair) would be quite diluted.

Short cycle length certainly makes sense to be correlated with pathogens. The lousy LG "TurboWash" only takes 28 minutes to do a full load of laundry but certainly doesn't get very much clean in that time.

I have to admit it was surprising that textiles have been identified as the source of hospital acquired infections. You'd think that even if the laundering didn't eliminate pathogens, it would greatly reduce them and make any clusters more diffuse.

Remember the way VW had a digital deception built in to some of their cars that adjusted the emissions when it detected they were being monitored?

Seems like I ended up with a software-controlled washer that is not very straightforward in its behavior and it may have something to do with energy rating.

There's no setting to get a hot rinse, not even a warm rinse, as expected. All those were taken away decades ago on purely mechanical models anyway, but at least a "hot" wash is still there. A mainstream US washer uses the household hot water supply though, they do not self-heat the water. You have two separate water inlets to the machine, one for hot water, one for cold.

You put in the laundry, start a hot cycle, and the drum starts to fill by opening only the hot water supply. It keeps filling whether the top lid is open or shut but it will not start agitating unless the lid is down.

When the lid is open, you can feel how hot the water is as it pours in.

As soon as you shut the lid, the cold water opens up too at full blast even though you just wanted hot. You can hear it and feel it for a second if you open the lid, but then that cuts off the cold and all you get is hot as long as it's open.

Saves a lot of energy when things are not as hot as people think they are.

I'm not familiar with the machines in this article, but you can look up the specs on them and see what you find.