Speaking Mandarin with an accent may affect people's impression of professionalism in some cases, but this is not absolute. Many factors affect this perception, including the type of accent, the relationship with the audience, and the content of the communication. In some industries or occasions, an accent may be seen as a symbol of personal characteristics or status, and it does not necessarily affect professionalism. In addition, the key lies in the clarity of communication and the ability to express. Even if you have an accent, as long as you can express your ideas clearly and communicate effectively with others, you will generally be considered professional. Therefore, it is important to improve your own language expression ability and expertise, rather than just pursuing the standardization of accents.