You can achieve that with a custom plugin that I maintain. To add a notification to a sidebar item you need to use the notification order item property.
Edit: I misunderstood your question, I thought that you wanted to add a new notification in a sidebar item. And what you want is to get those numbers for an automation.
You can check the number of issues with sensor.active_issues and the number of updates with this template:
{{
expand(states.update)
| selectattr('state', 'eq', 'on')
| list
| length
}}
For the notifications you can try with sensor.persistent_notifications.