End of Campaign mode vs Career

I know there have been threads about Campaign vs Career mode but this is not quite that. I am wondering if you continue playing after the campaign how similar is that to the career mode. I played about 100 hours of vanilla campaign but never finished it. Now I want to play with all the DLCs out. I am wondering if I should continue and finish the campaign and then keep playing it or start a career or restart the campaign. I kinda want to experience the story and wants to know if I can experience the new content after it finishes the same as in the career mode. Cheers.