Install Android 10 If You've Got Android Pie Problems
If you're dealing with bugs or performance problems on Android Pie, you might want to install Android 10 (or the latest version of it) right away because it could improve your Galaxy Note 9's performance.
Galaxy Note 9 users running Android 10 are noticing improved battery life, better connectivity, and a much smoother user interface. This doesn't come as much of a surprise.
Android updates, particularly major releases like Android 10, have been known to iron out common performance issues like severe battery drain, reboots, lag, and issues with connectivity (Wi-Fi, Bluetooth, cellular data, GPS).
If your Galaxy Note 9 is locked to a specific carrier, there's a chance your carrier tacks on additional bug fixes to your upgrade.
Samsung's version of Android 10 also comes with a few changes to Device Care (formerly known as Device Maintenance). With Android 10 on board, the battery usage graph now provides more detailed information.
These changes could help you get to the bottom of some of your issues much faster.