Acidities of (dimethylamino)acetophenone and (diphenylamino)acetophenone
Yeah, you're thinking in the right way! In the first structure, the hydrogen atom will not have a tendency to leave since the negative charge on the  corresponding conjugate base is destabilized due to lone pair of nitrogen atom(the N atom intensifies the negative charge on the  carbanion formed by donating its electrons in the p orbital of carbanion). Whereas in the second structure the lone pair of N atom is already dispersed in the two phenyl rings so the lone pairs have very less tendency of going into the p orbital of carbanion. Therefore, the second structure is more acidic since its conjugate base is more stable( or less destabilized) than the first structure