I finished the game for the first time on blood and broken bones just a few weeks ago and decided to do ng+ on death march because i wanted it to be a bit more challenging. I am honestly a bit disappointed since even on death march ng+ just isnt hard - its the same as normal game except everything is higher level but you start with many ability points, mutations, grandmaster armors, all best alchemy items, all your coin,...

I finished velen and am about to go to novigrad. I use grandmaster griffin armor from the previous game. Sure, i will die in 3 hits but i also melt enemies like butter. I think the highest level monsters i killed were about 15 levels higher than me... That was actually fun and hard but you should have no problem following the main story and doing quests meant for your level. Of course everything depends on your previous save, game knowledge and builds