You can obviously see a lot of answers to this question all over the internet. I'd still say a few things though.
IOS seems to run the game better compared to equivalent Android devices. PUBG M seems to be better optimized for IOS.You need a large screen. This is very important as you keep levelling up and start taking the game more and more seriously.You need a stable software with as thin a skin as possible. Stock android is best obviously but i feel MIUI inspite of being a heavy skin does really well with stability. (use the gaming mode)The stated requirements are BS. You need at least a SnapDragon 625 SOC. At least. And 3GB of ram on Android. Then too you will experience lag during intense moments while playing squads. Playing to rank is almost impossible like that.
So which device would i recommend. Get the Poco F1. The cooling tech, although a bit of a gimmick, does do something. It's definitely worth the 20k odd.
For a more premium feeling device with more punchy colours get a One Plus 6 / 6T. SAMSUNG Note 9 is crazy good too but more expensive obviously.
For cheaper options get either a RealMe 2 Pro or the MI A2. I recommend the A2 because of the stock android.
For the best experience possible import an ipad Pro 2018. The 120 Hz display + A12X is killer. 10x better experience than Iphone XS. Simply because of that insane refresh rate.
ASUS ROG Phone also would give you an almost similar experience.
Hope you liked what you read. Cheers :)