I agree about Juan in some aspects.
Like him trying to "protect" Lucrezia but he always cared more about the family name and reputation more than about Lucrezia or Cesare because that's what was expected from him... so when he killed Paolo he did it for that reason specifically.
I do believe he felt out of the circle thanks to Cesare and Lucrezia and he desperately wanted to be part of it, however he had all the attention from Rodrigo so
I rarely saw competition in regards to Lucrezia in this version but I definitely saw it in Borgia if I remember correctly. Lucrezia even bothers Cesare by picking Juan for certain things and stuff.