I had a KLR650 and now own a DR650. When I was much younger, one summer I took my KLR across USA and back .
DR is more capable off road than KLR. KLR will better for Highway and 2nd generation of KLR is a real PIG.
Both bikes can scrape the pegs in the twisties.
Most plated KTMs are not Dual Sport Bikes, they are street legal Enduro Bikes. I think KTM 550 and 690 can be used as a Dual Sport. All of the smaller models are not very road friendly for anything more than connecting the trails. Most people trailer them and do not ride them to the trails.
Than there is the cost of purchasing a Premium Enduro Bikes and short service intervals.
I upgraded the rear shock on my DR and installed RMZ 450 forks. I ride with slow people so even KTM Boys do not have to wait very long for me to catch up. I do not ride Single Track or Whoop de Doos at great speed and NJ Sugar Sand can be a pain in the ass, but I do have fun taking my DR places it has no business going.
Good Luck.