So I got info on a new phone model that have issues with the game (and worked after the Webview update): a tecno power 2 (this one I think https://www.naijatechguy.com/2018/12/tecno-pop2-power-price-and-specs.html - not one 100% sure, as I said data collection is sometime tricky).
And it has a MALI GPU!
Actually, a lot of person in Africa have this phone so it might explain why the issue is commonly spread there.
Anyway let's see how the latest update affects things, it might be that it fixes most of the problems.
It should fix the MALI GPU issue right? or is that different of the WebGL 2 bug?