You are logged in as admin at your S10 I believe and not as user or operator.
Try to turn off the "Set alarm notification" from any other IVMS-4500 device and log in only you as admin from S10 to see if there is a change.
View attachment 4211
Me logged in as admin and my wife as user or operator, no notifications to my wife.
Also make sure you use 4500 and not 4500 HD (worked abnormally on my Sammy).
Look if there is any new firmware versions for your DVR, that you can apply.
If IVMS is open working at your phone, still no silent alarm notifications showing as a numper at the top left corner of the app?
Check how the notifications are sent to a remote IVMS-4200 pc.
Did notifications ever worked at S10, f.e. with android 9 or one ui 1.0?
Double check if there is something on phone that stops IVMS notifications, like an antivirus or a battery optimization function, or something that put apps to sleep, or a "do not disturb", or app permissions .
And finally if someone in here has S10 and uses IVMS-4500, maybe can tell you something more than me, having an A50.
Hik and google f....ed me for 8 months with notifications, so I understand you completely.
Working at the same time 2 systems (NVR and software) with 2 network connections (local provider and private network) and 3 different cliends for the same Ip cams, just to make sure that Ivms works properly and I wont miss anything.
Hik stil f....ing me with remote playback playing only main stream, even if I record on both streams.
And everything bought from official Hik dealer for that, I don't have........F.........ING SUPPORT!!
Sorry for my English, not my mother language.