Your phone will get hot. If it gets too hot, the hardware-level thermal protection will kick in regardless of your apps. Consider using a phone cooler or playing in a cool environment.
Tap your multitasking button and "Lock" the app so the Android system doesn't kill it in the background. Crucial Warnings: Heat and Battery download max all cpu core no root
By "maxing" your cores, you force the CPU to stay at its highest frequency, ensuring peak performance without the lag spikes caused by the system trying to save power. Top Apps to Download for Maxing CPU Cores (No Root) Your phone will get hot