Even better idea: How about if you pressed the comma, it would temporarily cause all subsequent keystrokes to be interpreted as if with the Ctrl modifier? Then you could press another key to go back to inserting text. In fact, the editor could even start in the “comma” state because usually after opening a file, you want to first navigate around before inserting text. And to allow typing commas easily, we could just use the escape key instead. I'm sure no one has ever thought of this before.

You have just described Hydra:

https://github.com/abo-abo/hydra