My samsung s20fe 4g is 4 days old and I am having very similar issue. My old handset was 4000mAh and it lasted at least twice as long as this one. My 2 year old handset charged faster than this one by more than you'd expect considering they are both 25w fast charge and this one has a 500mAh more. The last handset cost me £200 less when I brought it and even now is still outlasting this one.
Straight away I turned off all the background features I don't use and lowered the 120hz to 60hz im losing around 10% an hour and its sitting in my pocket doing nothing.
I checked it in device care thinking it may help understand whats happening and its all on background apps. So naturally I try with all background apps closed and no difference. Disappointed, truly. This is my first Samsung and I had high hopes coming in. Now wished my old manufacturer wasn't loosing its Google play services as this isn't meeting the standards I expect for the price and brand reputation.
Can't get a solution to this issue and apps sleeping in the background should not be draining the battery to 25% by 9pm,whne the phone is unused all day. Any actual solutions or repairs that could be organised would be fantastic. €600 is an awful lot of money for a phone that I feel is not living up to its specifications.
Bought the FE 4G version 2 days ago (24 Dec 20) and I have the same issue. The power mode is currently set to optimised and adaptive battery option is on . Do I need to change the option? Highest Battery usage: Whatsapp 7.0% and Chrome is 4.8%.
I don't think the battery drain is related to device settings, it's probably more about the Samsung software, of which us as users have very little control.