Understanding Regional DLC

Hello Fellow Redditors/PS4...ers?,

I'm trying to wrap my head around Regional DLC and was hoping someone could explain the following situation: 1. Physical Game Disc is from Region 2 2. Account game has been played on is Region 1 based (US) 3. If I were to purchase DLC (Region 1) for the game, will it work? Or will I be limited to buying DLC for Region 2?

On a separate note, this has no effect on what account I make for my "Primary PS4" setting correct?

Thanks for the input in advance!