Couldn’t hear the fan noise on mine, 16GB RAM, even with LR, PS, Bridge and some browsers, etc open. That said, it was a dog for Lightroom and doing LOTS of memory swap, so just installed a MacBook Pro Max w/64GB RAM and 32 core GPU as my desktop (I use external monitors for printing). Holy Moly it smokes!
The Mini is totally fine and silent, but for Roon I think I’d rather run ROCK, as since 1.8 it’s been extremely stable on my NUC 7i5 in its Akasa case, and is dead simple to use and update.