Separate installation of drainage system
The drainage pipes in the kitchen and bathroom at home should be installed separately. If the bathroom is changed into a kitchen now, the drainage system of the kitchen will be connected with the drainage system of the bathroom.
Smell is inevitable.
There will always be an odor. Some people will choose to seal the floor drain in the bathroom, but in any case, it is difficult to guarantee that there will be no odor after you seal it, so there will always be a faint odor in the kitchen.