I can't play because of lag

As someone who's officially won one match in the Chinese server Challenger tournament, let me tell you: it's not the phone that matters, it's the internet. Home internet won't cut it. If you go to a shared house, even a studio apartment has good internet, so you'll be fine. If you can't get that, just turn on your mobile data, and it'll work well.

Anything's fine as long as it's not a total piece of junk phone.

Rather than your phone being bad, maybe your phone's storage is full? Even my trash phone runs fine.