(poly modelled) Avatar should only be used for non-deforming shapes (bed frame,etc..) or shapes that already went through simulation, and will be re-imported as Avatar to speed further simulation of fabrics on top of it.
So pillows and bedding,etc.. are always full fabrics in Marvelous. It's OK to use few at same time (3 pillows with 3 fillings plus bedding,etc..) but more you use it, the worse Marvelous becomes...not only slower, it will have issues with completing the simulation in all parts.