You can use User directory by FriendsOfFlarum
In extension specific permissions make sure to grant access for selected user group(s) (Everyone, Members, etc.).
In options for this extension make sure to turn on first option (link to user directory should be visible on frontpage). After that, user list is available at yoursite/users
For specific user you can click on username/nickname or avatar and go to i.e.: https://discuss.flarum.org/u/littlepeace2005
