How to download large files from iCloud drive to iPhone XR?

Live in a rural area, use iPhone cell for internet connection. When I NEED something from idrive it’s getting harder to retrieve (yea, I know, internet speed). I want to go back to simple. Store data that I need on iPhone (XR) and back it all up to a portable hard drive. The smaller files have been fairly easy to move, but some are bigger than 100gb and time out quickly. Is there a way to pull these down to my phone?

[Re-Titled by Moderator]

Original Title: pull data down from idrive, timing out