In my experience almost every microwave oven has terrible usability. It’s as if the design problem is so simple and the “correct” design (two independent, labeled, mechanical dials for time and power) is so obvious that everyone has to make their own version of it to look cool or sophisticated or something. I guess they never user test these things, because that doesn’t help sell more of them.
There really ought to be a usability certification for products like these, a verification by an independent organization that a typical user is able to operate the most important functionality with few or no errors.