Well the iris scanner has been replaced with Face recognition feature in S20. SPo2 sensor seemed inaccurate, i was using it in my s10, but i agree they must have improvised on it and retained this feature, it would have been a USP for samsung when co...
Sometimes the OTA updates causes few glitches. I got mine updated at the Samsung service center and had no problems afterwards. Well the battery drain depends on the number of apps installed and running in the background. Turn the Power Saving mode o...