I have a wall oven that's a couple months old and it preheats very rapidly. Unfortunately, it seems to achieve this by just lying about what temperature it's at. It's consistently 50°F to 75°F below the set temperature, as measured by a separate oven thermometer. The manufacturer anticipated this potential problem by including a boldface section in the manual saying not to use oven thermometers because they're "wildly inaccurate". Oh the irony of an electric oven using gaslighting.

For bonus points, even when the oven reaches the set temperature (which I now set higher than what I theoretically need) it doesn't bother to maintain that temperature, so I have to frequently turn the oven off and then back on again just to cook something properly. Once again ironically, this was the reason I replaced the old oven. Fortunately it was only $2500.