Actually, you may know the reason since you know about the protocols. We have to wait until the release their next update. I hope they'd release an x86 version next time. Running arm apps on x86 is not a pretty great idea for everyone. But, you can still play with performance issues. If you want to improve a little bit of performance. Follow these steps to slightly improve performance.
Clearing Dalvik Cache
Clearing Dalvik Cache may help your clear out caches and give you a slight boost in games. I suggest you to do in this in an interval of time ( e.g 2 or 3...
Actually, you're not getting what he is telling. They both are different engines. PUBG is Unreal and Free Fire is Unity. Unity's arm support doesn't work great. Also, everyone had played Free Fire with 60FPS are even getting 30~45FPS average. A sudden lag made the game unplayable. Hope free fire would release an x86 version next time.