No, the robot cannot overcome stairs between 2 floors as it can only manage thresholds up to a maximum height of 4 cm. The properties stated in the product data refer exclusively to the base station functions such as charging, automatic dust emptying and mopping system cleaning, without support for several floors or wet cleaning across floors. The climbing ability only applies to ground level obstacles such as door thresholds, and for 2 floors you need a second station. The information on multiple floors is not included in my data.

Yes, you can easily carry the Ecovacs X11 OmniCyclone downstairs, have it wet mop + vacuum there and then carry it back up to the main station.
It works autonomously downstairs, only the smart station functions (washing, emptying, drying, charging) are missing there.

I mean carrying it downstairs and then cleaning it wet and vacuuming it and then carrying it back up to the main stadium