Most of what you needed has been said already. Dense emulsified sausage is coming from a combination of two things, fat ground too fine, and over mixing which also causes that fat degrade further.
For starters change up your grind. Cut the meat into smaller cubes and only grind once though the plate, 7mm will work for Italian sausage for example. If your grinding once mix the fat back or pork shoulder in, if your grinding twice only put the pork in for the second grind.
spread the grind out flat over the largest area of your mixing tray, spread the spices out of the whole thing and then fold it all together nice and easy, never squeezing it or balling it.