Autosaving process takes huge time already (almost half a sec). I was thinking about overriding ISaveGameSystem::SaveGame and applying Runnable, but maybe there is another more elegant way?
Found a solution as always lol
I create multiple save slots with different actors, filtered by location or type in my case. You can split savegame differently.
Each saving process could be put in different frames using multithreading or simple DelayFrame.
While loading, I read all Save slots at once and append arrays to spawn actors the usual way.