Normally moving files between the main profile and Private Space can be a little cumbersome due to profile isolation. I recently discovered that Material Files app can have Private Space files integrated along with your main files. So you can manage files from both profiles all within the same app. First, make sure your private space is currently unlocked. Then in the main profile, open Material Files. At the top left choose 'Add storage...' > External storage and the android system file picker will let you add a folder from Private Space. It will be added as a bookmark in the sidebar. Now if you want to transfer files between your main profile and private space, all you need to do is cut from one folder and paste into another. Granted, this only works when private space is unlocked, but it makes transferring files really simple and painless!