Is there something on my iPad keyboard that works as an “undo” like Control-Z?
Yes. But it isn’t on your keyboard. Standard iPad and iPhone apps (like Mail and Notes) has a way to undo your last action (like typing or deleting a chunk of text. How do you achieve this wonder? It’s not obvious, but it is easy. The answer is to grab it firmly and just shake it. You’ll get a pop up that asks if you want to undo whatever action you just did.
My dad clued me in on this little jewel, cause he’s so smart and probably read the manual.