It should be a super simple feature to add to your terminal emulator: SCP works with a X,Y position. RCP just "jumps" there.
If you keep an accounting of how many lines you have displayed since then, you could alter the response to RCP by also doing the appropriate amount of scrolling: it should only take one variable, the deltaY to scroll.
If you want to test the idea, I think you could even use tmux and send commands to control the scrollback cf ahttps://superuser.com/questions/209437/how-do-i-scroll-in-tm...
I've used similar tricks with RCP/SCP but for simpler things: the only slight difficulty is the deltaY accounting, like when you are executing commands near the bottom of the screen because you must take into account that scolling will happen - but it's essentially similar to your idea.
So check https://github.com/csdvrx/bash-timestamping-sqlite/blob/main... and make sure you understand both how the __notbottom function works, and why PS0 needs an extra Esc[2a
Actually, now that I think more about your idea, it would be sweet to keep a SCP/RCP stack with multiple values, where you can push values with each SCP then pop them with RCP, say in sequence, or maybe just access the nth value with a different command that wouldn't pop them? That could be done nicely by augmenting RCP.
Also you could augment SCP with an optional flag to specify whether the terminal should scroll back upon RCP of this nth entry, and you'd have a great function that would be quite useful (ex: SCP with a jump bool when the return is non 0: you could make a shortcut to jump to the commands that have returned errors)
There's no reason to stop adding cool features to terminals: we're in a terminal renaissance!