Android has maximum heap sizes that are vastly smaller than total RAM. They can be as small as 16MB. 32MB is common. Browsers do get special treatment in some configurations. But, still, Android is designed to keep many runtime instances happy together in memory. Large in-memory data models don't work well in Android.
Therefore the value of large RAM is limited. Samsung makes their maximum heap sizes extraordinarily large, but that just makes bloatware bloatier.
If you want a big, complex software system on Android, break it up into multiple runtime instances, e.g. a shared data model in a ContentProvider component, and a suite of apps built around it. It you have a gigantic app and you are trying to do a straight port from iOS, you're going to have a bad time.