Heres a math problem to think about.
If your device has 95% battery remaining. That means its only used 5% total battery.
Now 100% of that 5% needs to be accounted for.
If you have not used your device much then screen time and other stuff will show low while other stuff will show high. Remember this percentage needs to be 100% of the total consumed, in this example its only 5% consumed.
So if 80% is Andriod system, thats only 80% of the 5% battery life consumed.
Frankly i get a full days use out of mine.
If my device were to get 6 hours or less then i would start to worry. If your device, with normal usage is lasting all day thne you should be ok.
If your device goes dead after a few hours,or with very little use is low at say 6 hours then yeah start to question stuff.
FYI if you look at qfnol31 last pic, it wil show he was in low to moderate signal with WIFI off, and that consumed a lot of battery.
Strong signal helps to consume less battery, being connected to WiFi also helps to consume less battery. These are the things that make a device last all day..