Poco f1 touch issue ( Armoured edition 8 gb 256 gb )

Hi, i'm vishnu from kerala and i recently just bought a Poco f1 through OLX. Now its been 1 month around. I bought this for playing pubg, when i play with the first time there is no issue this have. Later it have some error with firing button, it stops suddenly and i have to press again to continue firing. Then later one more error was occuerd that when i press and hold the scope button it wont move a bit. It stuck from the screen, so that time when i fire the aim goes up and cant controll recoil. It also having the trouble that without opening scope the aim cannot controll and recoil goes up. When in a close combat i cant fight well because of this issue, i die very early. I tried format my phone and reinstall pubg but its not resolved yet. I tried pubg lite and it have the same issue. Some times when i open whatsapp and press back from any groups it takes time to back, little delay for whatsapp. And also when i play any video in the gallery the video not play but the audio plays. I dont know what actually my issue with my phone. I also check the system check of touch and display that cross line and plus line and outline of the screen, it pass okay. Now i'm very disappoint because of the issue. Please help me :(
Thank you