RAM memory usage limit for Quest2 applications

I'm checking the memory usage of the app I'm developing. I think QUEST2's RAM (Random Access memory) is 6GB, but is there a limit to the amount of RAM that can be used by the app? Also, is there a recommended amount of RAM usage? 

The app I'm developing crashed when it exceeded 4GB of memory usage. Looking at this, it seems that there is no limit on RAM usage, and that the RAM that is left over after the OS and other uses of the Quest 2(maybe around 2GB) are taken into account can be used, but is this correct?