Dreame D20 Plus

It auto-empties into a large 5 L bag, so you go a long time between swaps, but the mop is rinsed and the water tank filled by hand.

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 multi-level maps, so you can fence off rooms across floors.