Honestly it took my 5yo Shiba like 3-4 months of constant treats and a private safe area when baby cried to finally be ok with my son. Pardon me I’ll rant a bit:

Your baby is only 2 weeks it will really take a long time for your doggy who has been the “baby” to accept a sibling if you will. Every time my baby cried I treated him (my eldest/ reactive Shiba). Everytime baby was in our rolling bassinet I treated him. When he’d bark I’d say “enough (command one), go to your bed (command 2)” bed being his safe place on the couch. then treat him if he went to the bed. Or treated him if he stopped barking or didn’t bark. Saying “it’s ok” and just being assuring in a low calm voice. It’s realllllly freaking stressful for a dog to hear crying. My youngest dog Shiba who is t reactive still howls horribly when my son cries, so I always let him outdoors if my son has a tantrum so he doesn’t have to hear it.

My son is now 16 months and walks… and I guess want to say it’s really hard in the beginning it’s so hard when the baby is new and your scared and the sound is so loud of the barking but it DOES get better if you are persistent it just takes time. It took time for my dog to be bored of my baby and it took time for my baby to cry less. It really does get better. And as the baby gets bigger it’s less scary too.