Galaxy Note9 Exynos (Unfortunately) changed original battery after 1.5 years of use (started to show decline at 1 year) and performance declined along with a Samsung members app request to change the battery as it had bad health. Accubattery app showed 80% (i know its not accurate).
So I went to an original Samsung Service Center and changed the battery and immediately after login using Samsung account the Samsung members app says battery health is still bad !! I asked the technician and he replied I should let it for 10 days so it can learn my usage. Now after waiting it is still showing bad health and my screen on time is still 4.5 hours maximum and I can't feel drastic improvement. So that's it, a mere 10% or so of performance felt ? Or I might have gotten a bad replacement ?