The Robo R1 is a good printer! And it looks quite professional, good enough to put it in the living room.
There are tools you can use to smoothen out your models and do the mesh repairs.
With proper finishing even low-poly models can look good for cosplay. Also consider using polyester filler to smoothen the printed parts further. This gets very hard and adds weight to the item. You can further add details with jigs, dies and stamps into the filler.
For a detailed 3D model for a cosplay artefact commissioned to an artist you have to think in the range of $250-500.
Thanks