If a red circle on Discord icon is an issue for you, then you need to do the following: If this dot is irritating, and you want to remove it, then you can try the below methods.
There is a black line on the dot, and it happens to be a status indicator. The second one tends to appear within the web application or the Discord desktop.
The first one is visible when there are unread messages, and it has a small white dot. The same happens in the case of any pinned messages to any server you are using. Therefore, if you are not on the app at the moment and another user sent you a message, the feature will let you know about that. As mentioned before, this dot happens to be a notification indicating that there are unread messages.
The situation is completely different when it comes to a Discord red circle on the taskbar.