Mc cares about Zoey, but as a friend (and he may not even be still that fond depending on the choices we as players make)
there isn't a single moment, in the present time of the game, before and after her return, in which MC seems to have any real regrets towards her, this regardless of what relationships he has. and it can't be otherwise because since her return it's always and only MC who talks about what he felt and how much he suffered. it doesn't matter how much time they spend together, but what they do in this time together.
the first time, in the scene on the bench, Zoey is justified in being fearful, after all she doesn't know what MC thinks of her (and in fact we can also choose to still be angry with her). where after MC humiliates himself by telling her how much he suffered by crying in the rain, she simply tells him that she missed him. after that what steps does she do?
they see each other once in MC's room and the big idea is to read his mother's diary...I imagine the real situation of a girl visiting a friend in his room alone and they decide to spend their time like that...

no steps forward. ok it will be a sign of trust, but still of MC towards Zoey, she very passive
then there's the barbecue where Zoey still wants MC to vent all his pain and afterwards she in no way tries to explain what she was feeling, had she at least talked about the past... ok, MC interrupts her, but she has nothing to say, or at least no urgency
this part then is overly homogenized, in that it makes little sense that Zoey's reaction is exactly the same whether MC is engaged and indifferent to Jacob's approach, or single and still jealous of her. but this is there in the game
she runs away, then denies herself on the phone, and she would also deny herself when MC shows up at her house. this is still a nonsensical scene, but the facts are that MC goes there because he regrets stopping her in talking at the barecue as he feared Zoey would reveal that at the time she did not reciprocate his feelings in any way, without any allusion to the current situation (I don't think when MC explains to Sage or Jill what he will do he is lying) and unbelievable, but that is exactly what Zoey does ... no problem between them, but no reciprocation.
then Zoey wisely decides to take advice from the person who gave her the worst advice of her life that put her in this unhappy situation and decides to swoop into MC's life like a wrecking ball.
there is no buildup, the scene was just postponed 3 chapters. very little was given to MC and the player to change their minds. then certainly those who adored Zoey at the interlude will still adore her, and those who want to see every scene in the game will screw up any relationship to see what happens (but on another save)
neither DPC nor Zoey even try.