Except Apple doesn't sell phones in China for lower prices
They are actually a bit more expensive than the same phone bought in the US. Any savings they might get from using Chinese NAND in iPhones sold in China is going back to Apple HQ.
You'd think Rubio would be in favor of a US company making profit off foreigners. The republicans of a few years ago would be, but today's MAGA republicans don't like that Apple is both very successful AND very "woke", because it challenges their "go woke, go broke" fantasy.