The other issue is he only listens when I raise my voice or he will just not give crap! I started with firmness but can't get his attention but if you raise your voice he is all ears.
How do you know if he is scared and fears as this is the last thing I want!
Count yourself lucky if he's listening to you at all! 😁 They're really good at being selectively deaf.
But yes @elbrant and @Zande are right that you need to "catch them in the act" so to speak. Ditto with rewards BTW. Speaking of which, if you don't want him on the sofa, you can use rewards to get him wanting to lounge in his dog bed.
I've never experienced a Basenji getting afraid of a correction so I don't think you need worry too much about that.