Screen on time is the worst possible way of measuring how good a phone uses its battery capacity.
There are massive differences in each person's usage of a device.
Even first using a device the software is learning usage patterns and can take a while to settle.
I have the P30 Pro as well, and the EMUI software has an aggressive power management. It's the one thing I've always complained about with that phone. It's far too aggressive.
Some other phones are less power managed to allow apps to be able to update and send notifications.
What apps you have on your phone will affect the battery life and how you use them.
Some apps will be constantly refreshing etc.
If you don't use some of the features on the phone, why not try disabling them.
The P30 Pro is a 4G phone S21 is a 5G device. So if you don't have 5G in your area, try turning that off. Especially if you don't have a 5G contract/ SIM
There are issues with Android 12 at the moment for which you'd have to wait for Google to sort out.
S21 is a good phone and blaming the hardware when that's probably not the issue is not right.
Currently from looking at the information you have provided, you have virtually a full 24 day of use if you used it for 24 hours.
So a few battery saving things like force stopping apps rarely used and looking at the features you don't use can save you further.
You can't compare the over aggressive power managed P30 Pro to the S21. They work and manage software in very different ways
I have the Z Fold 3 with supposed poor battery life. But it lasts me a full day and a lot more at times. Screen on time is really irrelevant as a measurement.
My post onthe Z Fold 3 battery life still in its learning phase shows it lasts well.
https://eu.community.samsung.com/t5/galaxy-z-fold-z-flip/battery-performance-z-fold-3/td-p/3901972I'm still getting the same if not better
