I'm not sure if I'm the only one experiencing this but on iOS and iPadOS devices I have never really noticed RAM bumps. I have the M2 iPad Pro, which has 8GB of RAM and I have tabs and apps having to refresh/reopen all the time, with all kind of apps (I know there are apps that are made to refresh constantly for security or other reasons). So I think that that added 4GB of RAM can easily be overrated, unless it can actually be used to good effect for intensive single tasks like exports (don't know for sure).
And I have had the same experience with iPhones, I have an old iPhone 13 here which I use to read stuff in my bed while my 17 is charging sometimes. Both devices keep as many apps in memory while my 17 has 4GB more.
I think that in some strange way RAM is more useful on iPhones because apparently the device needs it for processing images fast enough. To run those calculations of those camera features.