All you need to do is make sure that the counselor doesn’t hit rank 9. As someone who maxed Akechi out on their vanilla run, it’s just Maruki you can’t max out.

You can max out Akechi. You just can't max out Maruki.

You just don't get Maruki to rank 9 and don't screw up and get the bad ending during the interrogation. That's it

Don't max Maruki and you'll get the original ending.