That is a road of copying multiple envelopes and...
Thisss all time moving edit cursor...
One can say you can do that with automation items. Yes, but envelopes still are so crucial for Reaper's other functions that you can't fully migrate to AI only.
Reaper is very flexible when it comes to track content, you can put everything on track but selecting is not so flexible. Maybe not that so selecting like envelopes. Envelopes seem to be outdated mostly because you can select only one at the time for whole project.
I never used Cubase but when I see how it can select things I am scratching head to recreate this workflow with actions, scripts, cycle actions and other acrobatics.
I hope this script going to help but it is only script, we can't expect miracles.