Too many programs open in the background. Make sure to give permission to most of them to only run when opened and make sure you close all your tabs. When you have a lot of tabs open they are still pulling energy from your phone. My new phone was like that and it’s because I have a lot of games on them and kept switching from one game to another. Also, the higher specs of a game will cause your phone CPU to work harder. I could kill my battery charge a lot faster depending on which games I played.
So I got rid of the games that sucked my battery dry and only kept the simpler ones. Try doing these things and if your battery is still running hot then you may need a new phone. Oh, and make sure you have wifi off when you aren’t home. Your phone will keep roaming for a signal and that will also kill your battery. When home you can also cut off your blue tooth if you don’t need it for anything much.
Playing movies on your phone will also make your phone work harder and doing video calls can also make it work harder especially if you aren’t using wifi from your home.
Another thing. Don’t play games on your phone while charging. This will diminish your battery’s life.