In general I agree, if I have to choose one I prefer lockdown defense, but the true-blue unicorn in my opinion is the rare player who can do both at an elite level
It's very rare, I'm not the kind of person who thinks there's 32 #1D/#1C ect because there's that many teams, in my mind that distinction belongs to players who are the ideal version of fitting that role
Probably not a comprehensive list but I'll take a shot at it in no particular order, just sorted by even strength ice time the last couple years and combed through the names
Heiskanen
Dobson (short track record but he's tracking for it)
McAvoy
Hedman (declining now, was basically the prototype for a decade)
Fox
Makar
That might be it
There are a lot of great defenseman who provide either offense or defense at an elite level but are lacking on the other side of the puck like a Josi or a Slavin, who are excellent players, but they aren't truly the best option in all situations
There are also very well rounded D who are really great at both but are a touch below the elite of the league like Lindholm and Morrisey, I wouldn't call them #1s either
I'm pretty exclusive with this designation, it's a short list