I think the problem here is the A14 chip. I have ipadOS 14.1 and i have installed PUBG beta version and it works smooth. Since you updated the ipados to 14.2 , beta version must be getting choppy again. Once pubg gets an update this issue must get resolved hopefully. I saw in PUBG official instagram that pubg Metro Royal is gonna roll out on 10th November. So lets wait for that guys...Just a update guys : i have updated my ipad air 2020 to ipados 14.2 this morning and now even the pubg mobile beta version slutter and frame drop crazily.