I had the same concerns and came to this forum for help. it took me ages to find out why my phone was overheating n camera problems etc oh and battery life. After about a week now it's all good. nothing wrong with the phone to be honest. hardware all good. what I learnt is the way I set up my phone from my old phone. what I had to do is do a factory reset and start again.
do not use samsung switch to transfer everything.
make a list of all the apps you need on your new phone.
use your samsung cloud and Google account to transfer the essentials only. ie contacts, messages, calendar,
don't transfer any settings, home settings etc. and definitely don't transfer any apps. that's the biggest problem. basically some of the apps were conflicting with the new One UI / Android. what you have to do is reinstall all your apps directly from Google playstore or Galaxy store and install it from there. you should much better experience after that.
also note: if you can avoid using Chrome, then it is even better because chrome using more battery for some reason. but install it if u have to. its not that bad.
while doing all this, the phone can heat up a little but that's normal cos it's installing n setting up ur phone all at once. it's fine. Once everything settles, start using your phone as normal and let the phone learn how u use ut phone. give it about 5 days. it will heat up a little perhaps but that's fine. but if its really hot then contact samsung. also wipe cache partition after factory reset. look on YouTube on how to. hope this helps.
