akhilj66I was also facing the issue with pubg since sometime August. There was no frame drop but the whole game sped up like opponent moving very fast and me getting killed literally in 1-2 seconds. But then I tried everything and nothing worked. Then I saw that I had an experimental game profile which I loaded and am not facing that issue and game became little normal.
I am facing the same issue you said from August 2020, this month I got my motherboard replaced (under warranty) and I am still facing the same issues but to my surprise, the service center guy's Rog 2 works perfectly fine without any frame drops, it did a little bit in hot drops.
So I'll be getting my device serviced again this week. I think it has to be something with the hardware because if two phones are running on the same version of the software, how is it possible that one device faces the issue of frame drops and the other doesn't, there must be some problem with the hardware. You get your device serviced too.
If you ask guys who one device like OnePlus 7 they don't face any frame drop issue, except in hot drops. I have played on my friend's OP 7 and saw that his device was working perfectly fine.
I regret my decision of going with this so-called "gaming phone", piece of crap. Had a budget for OnePlus pro but went with Rog 2, one of the worst decisions I have ever made.