How do I see number of or icon for unread messages? My device: I use Android 9 on samsung galaxy s9.
Background: I believe there was a feature before (or maybe currently still, but I turned it off) about showing number of unread messages on apps like whatsapp, viber or the SMS app (and i guess gmail or facebook) or at the very least there's some kind of dot or something on a corner of the icon of such an app that indicates there exists at least 1 unread message (so the dot is an alternative to a specific number of unread messages).
My situation: I do not have such number or dot on icons on apps on my device. If I get a message on whatsapp or viber or regular SMS but say I have to install some updates and so my phone has to turn off or restart, then the notification of this message is gone.
Question: How do I see number or existence of unread messages on icons of apps such as viber and whatsapp and the SMS app?
I have tried looking this up, but

I wasn't able to find any articles specifically on Android 9 and Samsung Galaxy S9.

The solutions proposed in articles I've found on Android 9 but a different phone or on different versions of Android have not worked for me.

I've tried looking up some apps on the play store, but I haven't downloaded any because of the reviews.
I found out, both online and even in settings, badges go away when you swipe...Guess I'll have to resort to nova or some other launcher.

Some sources:

Source 1:
DudeThatsErin
It goes by what is in your status bar. If you swipe them away the number will disappear.
dark_sage94
They notification bar disappears for me once I read one text
LoyalRoyal18
Nova launcher does what you want, I believe.
https://www.reddit.com/r/GalaxyS9/comments/9e66n7/notifications_badge_on_icon_disappears_even/

Source 2:
Eh can't find anymore right now