currently, they don't, but the mobile operating systems do heavily cache applications in ram and those applications are getting pretty heavy, so instead of accessing bulk storage every time you launch an app, they are pretty much all sleeping in a low-cpu state with most of their content pre-loaded into ram.
Makes them snappier to switch apps and such, particularly with image or video heavy apps that want to be able to preload pages and pages of content to mindlessly scroll through while the internet connection loads more in the background.
Windows and MacOS has started doing a bit more of this, but still gets by with less ram as you tend to have a more powerful CPU and faster storage to not worry about an extra fraction of a second to switch between apps, but 0.5 seconds to switch apps on a phone can feel slow because we humans are simple dumb creatures with zero patience.
@worfamerryman@FragmentedChicken android is less memory efficient, because Java in lots of scenarios basically allocates the double of the memory that it needs for performance reasons. However, android with 6 or 8 GB is fine for 99% of users. 24 GB is nuts, and it's probably just for gaming.
Infinix Note 30 has an option where when plugging the charger and using the phone at the same time electricity would be used to feed the phone directly, instead of charging the battery (since charging the battery (33w fast charge) while using the phone causes it to heat and lose from its life) thus it stays cool during simultaneous usage and charging: now one could do work on a plugged phone without the risk of ruining the battery