I have my phone updated to the latest version and tried all the troubleshooting mentioned on the web including resetting and clearing cache.
I have figured that, in my case, my phone S10e does not go to deep sleep when the Bluetooth is turned on which is how I use my phone on regular basis as I got Bluetooth devices connected to it. When the Bluetooth is turned off it goes to deep sleep as usual.
Currently I have removed all the Bluetooth devices and testing my phone if it goes to deep sleep with Bluetooth ON but no devices connected to it.
EDIT: Just keeping the Bluetooth on inhibits the phone from going into deep sleep. I confirmed this after unpairing all the devices and removing apps related to them.