Excellent points sugar bun. Loved your deductions.
I have not seen the episode (or for that matter any episode😆) where Angad cries out for Kripa during her engagement. But yes, his change of heart is suspicious but it is not impossible.
I think the trip that they had made together brought out in Angad the human that was always lurking in him. Having been used to girls who kept throwing themselves over him and loving his image, Kripa was not only a refreshing change but also someone who stood up to him. He had started out with her in vengience and for some time even made her life hell. He was not really very cordial to her and for Angad's character, taking so much time just to get back at a girl would be just too much below him. He would have to have more motivation than just a slip of a girl crossing him everywhere. I think here,Kripa's constant rejection got to him and her innocence blew him up. His closeness with Dadi also meant he respects her a lot and hence would not really want to upset his fav grandparent by playing such a dirty game.
Of course the scenario you presented is not really impossible but here,a bit unlikely. Yes,he could be playing a game with her and also teach naina who is the boss of his life. Kill two birds with one stone. But somehow, the way he has become protective of her defies the logic that all the while he is just taking her for a ride. It's just too far fetched that he would play such an elaborate game just to get even with a girl.
But then, as someone said, Angad's deviousness would definitely mean more trp !!!!