According to the Ducati website the DesertX will come with the new liquid-cooled 937 cc Testastretta engine that produces 113 horsepower @ 9,000 rpm and 71 ft-lb of torque @ 7,750 rpm in the Multistrada 950.
Here's some updated information about the DesertX's motor.
The 2022 Ducati DesertX’s Testastretta 11° motor is based on the engine used in the Multistrada V2 and Monster. The 937cc V-twin with desmodromically actuated valves pump out 110 horsepower at 9250 rpm and 68 ft-lbs of torque at an approachable 6500 rpm. Changes to the clutch and gearbox improve shifting and save nearly four pounds. A quickshifter is standard for the six-speed transmission. 1st and 2nd gears are considerably lower than on the Multistrada V2, with the 3rd through 5th speeds geared incrementally lower. Sixth gear remains a touring-friendly overdrive.