Dealing with PNG's in the project

Hello all,

In my project I have estimate of 3000 thousand PNG's, w$$anonymous$$ch 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 t$$anonymous$$ng 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?