Dealing with PNG's in the project

Hello all,

In my project I have estimate of 3000 thousand PNG's, which combine different sprite animations. Each animation consist of 200-400 PNG's.

I'm doing a build for Oculus Go and only after I use Unity sprite packer the build is successful (otherwise the build would take ages and lag in Oculus).

The thing is Unity doesn't restore the cache of sprite packer and when restarting it needs to be packed again (very long process for me), and I wonder if it's possible to import a sprite atlas into unity or use a sprite packer plugin for that??

What is your way with dealing with so many PNG's?