KG_ Since than viber, slack etc apps stopped working. Cant send/receive viber messages, cant see my dms/channels in slack.
App optimization is highly unlikely to cause these issues. There's no point in delaying updates simply to avoid app optimization after a reboot.
To be clear, after these issues started, did you try another reboot of the phone?
If they persist after a reboot, it would be nice to know which apps fall into the category of "etc", and which symptoms they are exhibiting.