I have this controller and I've used it on my Android phone, FireTV and PC.

https://www.amazon.com/gp/product/B077L8656T/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

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https://smile.amazon.com/gp/product/B077L8656T/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
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I have this controller for my phone and I really like it. I have an android though, and I haven't tried it with this game in particular so YMMV

Wireless Android/iOS Game Controller, Retractable Telescopic PUBG Mobile Controller Joystick Gamepad with L3 R3 Buttons for iPhone and Android Phones https://smile.amazon.com/dp/B077L8656T/ref=cm_sw_r_apan_glt_fabc_P798QA93MACMBAMAS5QH?_encoding=UTF8&psc=1

edit: nvm it says "Doesn`t Work with iOS 13.4 Above System"

I'd rather recommend a Daqi or Bounabay, due to, like u/TheToonWolf mentioned, the volume/power buttons.

https://www.amazon.com/gp/product/B077L8656T/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

here:

https://drive.google.com/file/d/14YaLNlQ_kDJiq7fO_DFWfcsOv866XcDL/view?usp=sharing

Link to the amazon page if you need more info: https://www.amazon.com/Wireless-Controller-Retractable-Telescopic-Joystick/dp/B077L8656T

Been wanting to get one of these kind of controllers for my phone but 40+ bucks is a little much for me.