Hi, you say you have an ethernet port beside the Roku (ie behind or beside the TV) so would an inwall WAP do, this would use no real space. A Mikrotik inwall WAP that would give you the ability to stand up another net on that device which is bridged to a seperate SSID, and that net have a different DNS record.
Also you retain your data feed as its got front side ethernet ports aswell
https://www.gowifi.co.nz/accesspoints/rbwsap-5hac2nd.html
Cyril


