I’m not sure if this counts, but I use Readdle Documents, which is a file browser from before the files app on iOS, on my iPad as kind of a siloed collection of files and folders exclusively for work. I can still access those folders from my desktop finder at home through iCloud Drive just like anything else, but accessing all my personal files from the app on iPad (which is what I take to work) is a bit trickier, so it just keeps all my work things organized, focused, and away from my personal life.