Universal Control sounds like something that
might tempt me to update to Monterey.
Basically, it allows you to use your Mac keyboard and/or track pad on an iPad (iOS15.4 and later). It also works between two Macs, but that is already available with Sharing.
I say "
might tempt me" just because the iOS keyboard are so lame; no keys for control/option nor command. On the other hand, I rarely work on my iPad while using my Mac. Oh well, keep up the improvements in iOS, Apple. One day it might be as useful as a real operating system.
...you can copy data on one device with Command-C, move the pointer to another device, and paste into an app on the second device with Command-V
Obviously you still can't do the opposite.
Although, you can drag and drop
items (what kind?) off the iDevice onto a Mac.