Our 12 year undersink kitchen disposal wasn’t disposing. Being a simple contractors’ grade [cheap] it was immediately suspect. Maybe the cutting knives are dull… Tap water backs-up and the dishwasher is challenged to drain. Instead of summarily replacing the unit, try drain cleaner. Not the whimpy Drano™ or Liquid Plumber™ as seen on TV but something really caustic like: Pro Drain Opener – 93% sulfuric acid with the skull and cross bones warning. None of these are recommended for use in a disposal appliance but what’s to loose. Try two applications (1/2 cup wait 15 min). The trap downstream of the unit gets hot like a gun barrel so there is some good endothermic reaction going on. The pipes are good to go again after flushing with cool water. Check for leaks.