You need to install an extra page file for UAT Helper to build the UE binary you need a page file of 64GB, but standard memory is 32GB.
I have 16GB main memory RAM
I documented how to add pagefile.sys in this post in this thread
Can’t create C++ project ( or use C++ ) - General / Feedback & Requests - Epic Developer Community Forums (unrealengine.com)
Then I get about 6GB available and about 4 parrallel processes.
Use Windows Task Manager to check whats using memory and restart Windows 10 before you try and package a project