A M-ITX based board can allow for the more powerful processors to be used while remaining small. I built one when gen 8 processors were new and it runs ROCK just fine. It isn’t restricted by the power and heat limitations of a NUC despite being completely passive. It was an exercise in building a Roon server for Nucleus money but with superior performance so it has spurious bits like an audiophile network card. It was a success but the power was overkill for my modest collection and I went back to an 7th gen i7 NUC. The MOCK thread might be a good place to ask, and there is of course Uwe’s thread Evaluation of a Roon launch with millions of music titles
He might be a decent point of reference getting a Roon Server working with a massive collection.