But a switch by definition isolates all network ports. So core to audio endpoint will only be active for the brief moment that data is transferring between the two. Can the RFI/EMI from other inactive ports still pollute the Sooloos ports?

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).