In Davinci Resolve you MUST change your project settings to match the footage at the beginning of a new project BEFORE any footage is imported into the project, selecting 'change project settings to footage' (or whatever that pop up says) with the pop up window after adding footage does not do the trick, you'd think it would like AE or PP.
So, if that's what your doing, then it'll never be correct when you try to render in the delivery tab until you create a new project, update the project settings to 2.35:1 (in 3 places on the pop up project settings form to be safe, I think only 2 really matter for rendering) and then add your footage to the project.