This country has established law and rules that citizens must abide by. I didn’t create them but I still must follow them or face consequences or I can go to another country where I might not have to be burdened by the same set of laws.
It’s my God given right to move myself from point A to B, but if I want to do that within the framework of established transportation in this country, I have to submit to things like getting a DL, car registration, seatbelt laws, speed limits, etc. Non citizens aren’t exempt from this, neither would they be exempt from current US laws and regulations when it comes to obtaining firearms.
The right for an illegal to legally (within the US established rules and regulations) get and own a firearm while in this country should be an impossibility and a moot point to begin with. Again, how does an illegal obtain this firearm in a legal manner?