Nope, pretty much all have a duty cycle. Like 30 seconds on, 10 seconds off, and they keep repeating that or similar for however long the cook time is. If you listen closely you can hear the magnetron kick on and off.

I believe Panasonic was the only company that sold an inverter microwave that lowered the power output.

Black plastic doesn’t yellow like white. Microwaves are pretty much a commoditized item. Unless they’re trying to make it a “smart device” and sell you a subscription.

The Antique Microwave Oven that’s Better than Yours

Quality Ultra HD shitpost