If anyone is still here in 2025, I spent a lot of time optimizing my game, as indicated by other posts on this thread. I had stripped to the bare minimum and could not get anything to work. Texture sizes were astronomically low and everything (and I mean EVERYTHING) was optimized. My game scalability settings were perfected, some settings even taking the frame rate to below 30 fps.
I finally broke through this curse on day that I was working on my character BP. I noticed that as the blueprint grew in size, it would take longer and longer to compile.
On a hunch, I started collapsing logic all over the place. Whole groups of nodes, dedicated to certain things, all became a single node. To my surprise, the BP would now compile much faster, almost instantly.
So, I went through my entire project, looking at BPs with a ton of logic, and began collapsing chunks of logic down to single nodes. One that seemed to help tremendously was my HUD.
I compiled everything and built out my game to test, deploying both as sideload and from the play store. The game now runs flawlessly with no heat on milder settings, and very little warmth on max settings. The battery drain is practically eliminated as a result of this.
I hope this helps someone else somewhere.