You said is new so maybe you haven’t properly set it up. Meaning Location services, background app refresh, notifications, etc. here’s some personal tips:
I have Background App Refresh OFF on almost all apps cuz pretty much NONE requieres to do sketchy stuff on the background.
For location services, on System Services if you’re not a hardcore user, pretty much you just need 3-5 options ON.
Another tip is to Try to use display brightness under 50% all the time , 35% is perfect for indoors, you could also set an automation for brightness level when opening certain apps. I have it for example when opening some games and some other “demanding processor” apps, which will heat the phone and if brightness is high it will make the phone hotter.
Using cellular data make the phone heat, try to use WiFi when posible.
kill apps from multitasking when they’re very cpu demanding, aka games, YouTube, among others since they waiting time for them to go “sleep mode” is longer than what people think and they’ll be “on hold/standby” on the background waiting for you.
If you don’t use Bluetooth at all, turn it off* altho be aware that Bluetooth needs to be turned ON in order for Location Services to work
Check your Mail accounts Fetching options, I have 9 accounts on default iOS Mail app, 6 are set to fetch manually, the rest to Push every 30 minutes.
Check for permissions of apps to use Cellular Data; some apps like iCloud Drive are turned ON by default so they can (if not set otherwise) use cellular data to do background tasks.
Pick Cellular Data Voice and Data mode to 5G ON (if available for your carrier) usually it’s on Auto by default which will fluctuate the connection all the time using more battery and system processes aka cpu.
Don’t use widgets cuz honestly theyre just a fancy whim LOL.