The floor drain smells, will it float into the washing machine from the washing machine drain pipe?

I will.

As long as the drain pipe is placed on the U-shaped line in front of the wall drain, it will naturally form an odor-resistant water block.

The so-called odor-resistant floor drain must have this U-shaped bend, so as to store water and block odor. If you install a U-bend in the hole in the wall, it will take up a lot of space. So you can bend this U-shape against the wall with the soft drain pipe of the washing machine, which can deodorize it.