I need to transfer files from my Chromebook and / or Android phone to my iPhone Xs and thus far can't come up with any good options. I can't use any of the file transfer apps that require both devices to be on the same network, and instead need them to be directly connected to eachother over usb. When I connect my iPhone to my Chromebook I see a directory containing my photos and can read from them, bit not write to them. My Linux laptop detects several directories when plugged in, but can't write to any of them either. I need that key ability to write a file to my phone from any other computer / phone over USB.