I must be the opposite because I reckon I love my newborns the most and then as they get older, and more stubborn, and argue with me, and whinge, and whine and generally drive me insane the novelty wears off
OP give it time. You're learning the juggle nice the second baby comes along, and everything with your oldest will feel safe and familiar. I have 3 amazing kids which I love equally, but they have different qualities which I really notice now and appreciate in different ways. I love that DD1 is so incredibly helpful to me, that dd2 is the kindest person who would literally hand everything she owns to her brother, and how DS makes us all laugh all the time.
It takes time, but you'll definitely get there.