lol just like dealing with some of the worst Ryu’s in the world, I can fall into this trap still with Akuma (oddly enough I just spent a week getting Cody from 0bp to B+ rank, and had a like 95% win rate versus Akumas, good ones and ones who use this “tactic”). Whether Gouki zones hard or vortexes, this match is a pain in the ass for Cody.
This isn’t something just low level Akumas do (Helnova does it to me here and there, and he’s one of best Akumas I’ve played). It’s a common part of his zoning game. Cody has a few options around the fireball game of Akuma. Ex Ruffian Kick will go under ground fireballs and air fireballs that are still pretty high. You can cr. MK under air fireballs easy enough as well. Red ones too. You can focus absorb them and dash in. If you’re getting hit by his tatsu after focus absorbing an air fireball, you’re either doing it when he’s perfectly spaced it to the ground or you are spending too much time charging the focus attack. Unless you meant a regular dash under a fireball, which seems weird that you would get hit with a tatsu still.
You should also be using your rocks. Remember, you don’t have to do HP rocks, you can do LP rocks if it’ll hit the FB. LP rocks has the fastest recovery. Of course, once you stop throwing rocks, every Akuma is going to try to catch you with a demon flip.
Up close you should have that zonk ready. If he throws a ground fireball, murder him. If he throws an air fireball, and you’re that close, you should be able to dash, cr. MK or zonk under it and punish it. Once you’re in, be ready for that teleport, it is undoubtly coming.
When it comes to his red fireballs, it’s pretty simple. They are slow with garbage recovery. Gives you plenty of time to move forward. Also, HP rocks will make him put that tool away when he gets hit once or twice out of the start-up.
As for learning Cody, you’re still new to him, so a big part of it is just putting in the hours with the character, reacting to situations with ideal punishes and combos.
All that said, you could have asked this is the match-up thread or at the very least, the “Shoto Army” thread.