I would go DW front bar with Nirnhoned main-hand and Sharpened off-hand, then either S&B or resto backbar
Although I have a friend who refuses to use anything other than S&B and it works decently well for him.
Unfortunately the good old days where DW or S&B were viable are long gone there have been so many nerfs so that they have made magdk into a one build pony... And it's just sad.
I already have a character like this. Works fine for the types of content I like doing - which includes soloing world bosses. I don't use a magicka weapon at all on the character.
To add - there are multiple ways to make it work, honestly. I develop characters over "builds" so my choices are more informed by the character concept I'm going for. General tips I would have:
You won't be able to spam damaging abilities. Rely on your DoTs. As a DK you have a lot of them anyway, so you can apply your DoTs and then let them do the work as your magicka recovers.
Your light/heavy attacks will suck. There's no way around that, but they can be made a bit more effective if you run the infused enchantment. That way you get okay damage when your enchantment procs.
Sources of passive damage are your friend. I would definitely recommend one of several monster sets or 5-piece sets that do damage when they proc.
You will need decent magicka regen, because you can't restore resources with heavy attacks. If you are like me and also generally refuse to use potions, there are times you will need to use them while soloing those world bosses.
Here is my MDK melee weapon with >4K spell damage and 2k regen I have tweaked it since making this video though. I really need to upload the build vid for it.
The passives from 2H are just better imo than the DW.
True dw only gives a tiny little bit more dmg bc of sharpened off hand. But 2h offers alot of nice stuff like 30% stam recovery or follow up on heavy attack. Or even a snare removal.
If you run a bar with weapon/shield, you can build your other bar for a burst combo. Use your weapon/shield bar to gradually wear down their health/resources, and switch to the burst at the right moment to finish them off.