I find that on PUBG Mobile, if you find it smooth enough, there's no real need to check the fps - unlike the PC version where there's a lot more granulity, that affects things like rate of fire.

As usual, I figure you've tried turn off anti aliasing, use smooth instead of full?

But if PUBG Mobile is your main game...there might be a much better way to get the performance you need. I would say out the actual solution, but I would trigger some hate from 'non users of the same brand'. PS: If you follow the competitive scene, there is some really really significant proof (and no, it doesn't involve cheats / trigger or using a tablet).