my oldest dog has been acting up like crazy since we have gotten our puppy. has pooped on the floor…

my oldest dog has been acting up like crazy since we have gotten our puppy. has pooped on the floor every single day without even trying to let anyone know he has to potty & he NEVER does that. in the kitty litter eating cat poop, something else he has never done before. has been tearing open trash & having it around the house, once again never done. & I have just caught him on the KITCHEN COUNTER. my cat does that but never him he hasn't done that for almost 3 years since we left a lemon cake on the kitchen table. idk what to do with his attention seeking behavior anymore.