Android Oreo changed the way notifications are handled. Previously, apps did their own thing to provide notification badges. The apps either had to support the badges for their icons, or launchers did that for apps like how Samsung used to do it, or third party ones like Nova via the unread plugin.
Because a lot of app developers don't support the badges yet people want them, Android devs reworked the notifications and added notification dots/badges tied to the notification panel. Due to these reworking, Samsung also had to alter how they handle notifications as well to use the system setup.
So the only way now to get the old methods is to use a different launcher that still provides that old badge service, like Nova Prime with Tesla Unread.