What is the best way to compress EXR project files after Completion??

I finished my project after rendering and now I find myself in a very complicated situation.   I have Original  EXR files as my source  for After Effects after I rendered in Unreal Engine as PIZ.  Through Unreal Engine, I made many sub-directories folders since it doesn't do the job  Multi-renderPasses and overall it's 600 GB sizes.

I do not want to lose cryptomatte if I compress it and In After Effects you can pre-render so what is the way to replace my original footage with a smaller size and lossless quality?