Never let your Denon go for a belt drive!!!
Measure the pivot to spindle distance and search for the proper effective length of the potential new arm.
ie: pivot=221.7 for eff. length=239
pivot=232.4 for eff. length=249
pivot=222 for eff. length=239.3
pivot=230 for eff. length=246.736
So, you can see if the pivot you allready have is close to 222 or closer to 230 and proceed to find a decent new arm for your Denon that matches the right eff. length.
Needless to say that you are going to loose more money if you consider to change both your defective arm & also your excellent table!!!
My advice is to give your best effort to support your turntable with integrity. Buy the best arm you can afford and don't worry for the proper height -you can use cork of different millimetres under your LP mat, or you can change the rubber mat for a graphite or a copper one in the future-, you may add some nice footers & a base platform, you can let a technician to upgrade the internal electronic components to the present technology ICs & capacitors and in the end you will never have to worry for the "new & improved" plastic belt-drives with their coin-like motors and the endless upgrade path.
Do whatever is possible just don't let it go...