From the perspective of geomantic omen, a dumb mouth can be regarded as a circle, while in China traditional culture, a circle is usually regarded as an ominous shape because it symbolizes incompleteness and rupture. Therefore, installing a circular dumb mouth between the living room and the corridor may have a certain impact on Feng Shui.
However, the views on Feng Shui vary from person to person, and different people have different views and beliefs. If you have any questions or concerns about Feng Shui, I suggest you consult a professional Feng Shui master or architect, who can provide more accurate advice and guidance.