It’s called Garbage Collect after
The tutorial doesn’t show it as it’s a new feature. But it’s the same place where you can set up the frame skip and if it renders 2 eyes or only 1. (the camera rig)
But im not sure this will fix it for you. The crashes i had were I think related to memory and although Garbage Collect did help a bit it still crashed untill i did it through UE-editor by hitting play.
I have 4gb gpu and use 5-10 on Garbage Collect after.