Hello Tructt,
Welcome to Apple Support Communities! I see that you're experiencing some issues with Wi-Fi, audio, and the temperature of your iPhone 7 Plus when playing PUBG. I would be happy to help provide more information to consider.
It is normal to feel your device get warm when playing a graphics-intensive game like this for an extended period of time. If your iPhone exceeds an acceptable temperature threshold, you'll see a warning appear and some features may be temporarily disabled. Consider moving your iPhone to a cooler environment, removing the case to cool off the device if there is one, or avoid playing graphics-intensive games for an extended time while the iPhone is connected to a charger to prevent that from happening:
Keeping iPhone, iPad, and iPod touch within acceptable operating temperatures - Apple Support
As far as the Wi-Fi and audio issues that you're experiencing, does this only happen after playing PUBG? If so, here are some additional steps to help further isolate potential causes:
If an app unexpectedly quits, stops responding, or won’t open - Apple Support
Cheers!