Search in Roon has been brutally slow for me ever since the advent of Roon 2.0. I’ve reported this several times to Roon support (as have others). The most recent release has made it even worse. See:
https://community.roonlabs.com/t/poor-performance-when-filtering-searching-in-tracks-view/244977/32
https://community.roonlabs.com/t/roon-performance-terribly-slow-since-v-2-build-1221/236992/103