I can’t store or buy a gun in the us.
Why not? There are at least a dozen US states where it is legal for a non-resident legal alien to purchase/acquire a handgun.
All you need is to have a valid Admission Number (You have to ask customs to stamp your passport and issue you the AN, which they don't normally do), and be able to pass a NICS background check, which will be pretty easy if you have never been cited for any criminal offences in the US.
If you are allowed to legally own it, you can legally store it just about anywhere in most states.
If you can't legally buy a gun in the us then how do you get a ccw permit?
By submitting an application, by mail, to the NH State Police. No photo, no course, no test, no trouble. Two page application, background check and $100 USD and you are cleared for five years of freedom carry. You have reciprocity in twenty something states, and when you factor the constitutional carry states you are good to go in about 65% of US land mass.
Idaho has better reciprocity than NH, and they will also issue to non-resident legal aliens, but they make you apply in person. If the national reciprocity bill ever clears the legislature, I suspect a lot of the non-resident permits might disappear, or might not be recognized.