At that point you're probably better off waiting for the iPhone XI to come out which will drive XS prices down to around $600. Can you swing by on a backup phone for two months? Like an old 6S or 7?
After the XS was launched last year, I was able to pick up a used X with AppleCare for only $650. So don't pay the high prices now, the previous models will drop to $600 when the new iPhone comes out.