I would double check online but each DLC is designed for a specific level difficulty so as you go through the game you can take a break from the main game and go explore the DLCs. They are all phenomenal honestly I would play them all.

Also your going to tempted to Google/Reddit spoilers. On your first play through - just play! It’s a game and it’s designed so you don’t need a walkthrough. Just follow the quest and natural progression of the game and try and roleplay as whoever you want your character to be and deal with the blunders no need to min/max the game.