Does the CG of an aircraft have an effect on tendency to Dutch roll and if so what CG is worse?
No, generally not.
However, if an aircraft has a tendency to dutch roll due to its design deficiency, aft CG can make it somewhat worse.
This can be confirmed by flying a type that
did dutch roll (sometimes, divergent), the early models of the Boeing 707.
Take the long body early intercontinental model, the -320 straightpipe, as a good example.
A dutch rolling son of a gun, if you got it going.
However, with the center tank full (CG forward), more stable.
Center tank empty (but with wing tanks nearly full), aft CG prevailed, and the dutch roll became more severe.
Now, I fully expect that some will disagree with my statements, however, I flew these old airplanes, so I do know many of their undesirable tendencies....first hand, make no mistake.