It’s not that Android is less efficient with RAM, it’s that Android and iOS take drastically different approaches to RAM/background app management. iOS uses RAM compression (same as how its worked on macOS since Maverick.) iOS can compress a background app from say 350mb down to barely 10mb in ram, and uncompress it back instantly when called upon for use again. Android doesn’t do this, their solution is far less elegant and is to just throw more RAM at it. This is why Androids often have 4-8gb of RAM where iOS can manage often more apps in the background without a reload with far less.
Edit to add a video explaining this.