I have iOS14 beta 4 and it’s TERRIBLE. My iPhone 11 Pro Max battery gets sooooo hot right under the camera when browsing the web or watching a YouTube video or just using the phone in general. I don’t know what the issue could be. I did a hard reset and still gets firey hot. Then to protect itsself, the screen brightness dims until I stop using the phone as it cools
Same phone, same beta. Works fine and it’s not getting hot. We see that some of us have problems with Betas, some not. Sad for you. I would try to install it again and see if the issue will be solved.