>>32842482But 5Ds isn't the synchro dimension, the Synchro Dimension is more accurately an alternate version of 5Ds.
With that said, there's no denying that something went wrong with writing. Be it the writers shit the bed somewhere along the way, or corporate got in the way like in XY, what matters is that nothing make sense in the Fusion arc, and the ending feels like the type of thing that the Main Character is dreaming of, but is supposed to wake up from. but they don't, that's really just the ending.