Background Services have always been killed on short notice. AFAIK, the OS regularly restarts them, even if it is completely idle with zero memory pressure. It used to be that way in KitKat and prior versions too. Using a Foreground Service have always been a hard requirement for persistent network connection — unless you were ok with reestablishing the connection every hour.
"App xyz is running in the background" or "App xyz is using battery" aren't normally shown when you foreground Notification is properly constructed. If you correctly set icon, text, notification channel and other properties, the notification bar should have only your notification and nothing else. At least it have always worked that way on devices I own.
"App xyz is running in the background" or "App xyz is using battery" aren't normally shown when you foreground Notification is properly constructed. If you correctly set icon, text, notification channel and other properties, the notification bar should have only your notification and nothing else. At least it have always worked that way on devices I own.