https://wccftech.com/google-investigating-pixel-5a-overheating/

On paper, the Pixel 5a 5G is one of the best mid-rangers that you can purchase if you are on a tight budget, if not for one small problem; it overheats rapidly. Thankfully, Google has taken notice of the issue and has decided to commence a little investigation of its own to isolate the problem.

Apparently, the problem is related to the camera app. Previously, lots of publications stated that the Pixel 5a would overheat in around five minutes while recording at 4K 60FPS. Unfortunately, the issue has trickled down to lower resolutions, too, with Android Central reporting that after capturing a few images and recording at the 1080p resolution, the mid-ranger would start giving a warning sign that it is overheating.