Can you still make QuickTime to store temporary recordings on another drive?
It seems that Apple doesn't want you to do this for whatever reason, so they prevent the symbolic link hack from working at the level of the Data/ subdirectory. After fooling around with this, I found a workable solution one level up:

$ cd ~/Library/Containers/
$ mv com.apple.QuickTimePlayerX/ com.apple.QuickTimePlayerX.backup/
$ ln -s /Volumes/&lt;NAME_OF_VOLUME&gt;/com.apple.QuickTimePlayerX/ .


No need for a double link trick this time around.