Noted. If you are absolutely certain its the app and since your situation seems rather severe. You should know what to do. Life takes priority and the smartphone is critical in our day to day life these days.
Having said that, you are the rare few out of millions thats spoken up on this. To most of us, its fine. My battery last a full 12 hours while on TE19 app which i go through at the start of every month during player purchasing frenzy at auctions but i did selectively choose a phone with a massive battery power storage.
If i were you i would back up all information and reset phone to factory settings. Trojan horses/viruses and some hidden installations might be running in the background that drain your battery life to get access to your files and information. If not, carry a powerbank. I play a game called mobile legends with my mates and it really requires power. Much much more than TE, i use a powerbank for this when we do all nighters