Some folks just looove to save a tiny bit of budget shooting so they can multiply their budget in post. Keylight in AE will be your buddy in this case. A helpful hint for render times, if you use a regular color keyer first, you can remove much info that keylight would have had to do. Add it after the color keyer(s) and you’ll save a lot of time.
It just takes time in the chair. You’ll notice if you mouse over icons, you’ll be flagged as to what they do. Don’t get frustrated. Break in times vary from user to user.
You kind of migrated backwards in today’s day in age, didn’t you?