It's more comparing in the state that they both felt pretty helpless and needed a lot of help from others to get through it. Other than Aura, Apollo never really had anyone in his side in his sceptism against Athena. Ultimately Apollo's was wrong, and Athena and Phoenix were right. This is where the link between the two come in. Despite everything that could go wrong, nothing does in the cannon endings. Everything works out fir the better. Both have potential bad endings such as the "Miricle Never Happened", or in the case if DD two bad endings where either the case is lost and Simon is put to death, or Athena goes to jail instead.
The difference between what Phoenix went through and what Apollo went through was the test of what mattered most to Phoenix (the truth or Maya's safety), and Apollo's was a battle of distrust. Based on everything that Apollo has gone through, it's safe to say he probably has trust issues. He wanted to find the truth in Clay's death but his distrust in Athena lead him the wrong way. Rather than fighting between two things he cared deeply about, it was more of the turmoil of trust in one's client. Because Apollo did not believe in Athena, he went astray and almost convicted a inocent person. I'll admit that it is a bit hard to compare them in this particular case, Phoenix had his morals of advocating for the truth above all else challenged, Apollo faced his ability to believe in his client above all else, and Athena had to face her past and belive in herself.
What I am really saying is every character faced something bad, but in the end it worked out in the best possible way. Athena is no different than the other two for facing her demons have it work out for the better.
I wouldn't say Klavier was spoon feeding the answers, he was just nicer. If you take away the emotion behind Klavier and past prosecutors, they are asking the same questions, just in a different way. Just because Klavier is nicer does not mean he is an easier opponent than Edgeworth, Franziska, or Godot, it's just an illusion because he does not talk down to you like the other three.