Answering the first question about whether it is normal for the game to crash in Nox Player, this emulator has certain flaws with this game, I personally recommend real cell phones and even so it may not work correctly on all of them.
Answering the second question about what I mean by "do not abuse the mod in multiplayer mode", I mean do not be too flashy, do not use the "automatically win" option in multiplayer too many times against real people; the mod is not automatically detected by Anticheat, but if a developer looks at your account, he finds anomalies such as that you have won quickly in less than 1 minute, that would be strange and more so without harming the opponent, also avoid getting into the global top with a new account it would be very strange and more so if you win the games with basic weapons.
And finally answering the last question that why the available store does not appear, this happens because the game does not find a connection with the Google Playstore to obtain the prices of the objects, so if you want to see the objects in the store you must have internet and log in with your Google account, but this does not happen because you have been banned.