Ecovacs DEEBOT N20 Plus

The dock auto-empties into a 1.5 L bag, but the mop is not auto-washed, so you rinse the pad and fill the 220 mL water tank yourself.

The robot is 3.8 inches tall, so it slides under most sofas and cabinets, though very low furniture may be tight.

It clears obstacles up to 20 mm, so it handles standard door sills but may stop at taller thresholds.

Yes. It supports no-go zones and stores maps for up to 4 levels, so you can fence off rooms across floors.