Is Roon Nucleus the best choice for Roon Core and as server?

I am in the market for a Roon Core and a server for my stored music Including high res, cd quality and some old MP3 I cannot find elsewhere. Some servers I have looked at suggest keeping the Roon Core separate due to the heavy volume of metadata. As I don’t have that much stored music, I would prefer to do these two functions in one unit and spend more on the streamer and the DAC. Is Nucleus by Roon the best choice? I see an RS9 being advertised but can’t find any information in it.