TL;DR: Recuva Deep Scan on a 500GB drive reports that to recover all data that was formatted, I need 7 THOUSAND GB of space.
So ignoring the fact that I'm clearly an idiot due to how I got myself into this mess, I don't think I'm so stupid as to messing up the recovery aspect. What step or whatever am I missing that Recuva is deciding a less than 500GB set of files (size of drive is 500 GB, wasn't full when I formatted it) needs to have over 7 thousand GB of space to recover said files???
Whilst it is possible that more space is required for recovery than the original disk size (due to multiple entries for deleted files pointing to the same disk space), a factor of 14 to 1 is rather excessive. I'd suggest ignoring it but I don't think that Recuva will let you go ahead without the space being available.
You could look at the list of found files and see if there are any obvious errors, such as a few very large files, and drop these from your recovery. Or recover a subset of the files at a time, if that is either desired or possible.