The compliance of your cartridge is quoted by Zu as 5cu which is stiff for your arm if 5cu is really the correct number to use. Japanese manufacturers specify the compliance at 100 Hz instead of 10 Hz standard. A practice is to derive the compliance at 10 Hz by multiplying it by 1.5 or 2. That would place the compliance of your cartridge between 7.5 to 10 cu which is better for your arm. Overall though, this cartridge may be too stiff for your arm. Regarding your arm, did you check the amount of damping oil in the well? VPI says “if you feel the sound to be constricted (overly damped), remove some of the fluid.” You can check your guide for advice on the amount of oil and whether to thin it.
I use a Denon DL-103r in a Denon tonearm with Denon AU-320 step up transformer (SUT). The r version of this cartridge has a 14 Ohm impedance but still works well with the transformer at the transformer’s 40 Ohm setting. Your cartridge has the 40 Ohm impedance that the transformer expects. These transformers are always available on the auction site for $350 or less including shipping from Japan. If you don’t mind spending a little more money a SUT might be worth a try. You can always sell it on the same site if you don’t like it and get most of your money back. The input impedance of your phono stage to work with the transformer would be about 47K, i.e., the moving magnet input or setting.
The Denon DL-103 is a classic cartridge desired for its overall realistic effect. It will not necessarily impress with extreme detail or other sensational sonic effects. I recommend you continue to look at your setup and see where adjustments can be made. A SUT will do some of the work of your phono preamp and clear up any impedance issues. This could get things to sound better overall.