Is it okay to always cover the lid of the smart toilet after use, and the power cord inside?

Yes, put it under the bed or other hidden place after use.

Yes, especially after pooping, if we don't cover those bacteria, we all put our toothbrushes and cups in the bathroom, in that case, the toothbrushes are covered with bacteria, so we must cover them.

If your poop is more smelly, cover it, if your poop is very fragrant, then it is open, but from a philosophical point of view, closing or opening is just a change in your consciousness, Buddhism often says that there is and is not in your heart, if you think that he is open, even if it is closed, it is open, don't use a very vulgar vision to say that this is idealism, if you feel modern quantum physics, then you will understand that anything, physical quantities must be measured and defined by people to be meaningful, If there is no measurement and definition, then this physical quantity is meaningless, for example, if you look at an object is red, then in the eyes of the horse it is not red, but blue, this is the reason for the different angles of observation, so it doesn't matter if it is closed or open, the key is to see if your heart is closed or open? As the saying goes: sometimes there is nature in the heart, and there is no time in the heart.

Yes, but it's best not to do this, as it will increase the efficiency of the toilet.

When flushing, it is covered with hygiene.