It clearly depends on who is available, not what. You can't just blindly say you want X position because that's what we need the most.
No team is so great that if the best player in the draft is sitting there, but you don't need him, (*unless it's a QB) you wouldn't take him? BS, you take him anyway. How many players on this team make you say no, he's so good you can't replace him or even need to add to my position group. Martin, Micah and Lamb are the closest things we have to that here. But none of them would keep me from adding another stud caliber player at their position.
Overall, if you're asking me the 1 position (*other than QB) that is usually best taken in RD 1, it's Edge rusher. Almost all stud pass rushers come from RD 1.
But to answer the question I think you're asking; which is what we should do this year, if we're given equally talented top rated players at all positions (*other than QB)? I'd still probably take a DE. Or LB or DT.
*I'm not saying Dak is that guy, I'm just saying a top QB doesn't need to be added if you are ready blessed with one. All other positions are on the table.