@mydiane, that's what we do also. Our laptop is ethernet wired and we run an hdmi cord from there to the TV. Works beautifully and we tossed our Roku. We also disabled the wifi module inside TV because that emits even if the TV is wired and even if it's turned off. The only thing that stops it is disconnecting the power. No more RF here.
@dfgsrzwer, you're wrong in assuming they have a router.
You can power up a roku or a smart TV on a deserted island where there is no wifi and no router, and the roku will still emit RF. The only way to stop it is to unplug from the electrical power.
Exactly, MartyPA. We can't and don't use Roku or any streaming device. Once in a great while I will need to turn on the wifi for a couple of minutes and find that I immediately experience panic. The anxiety is intense and unbearable. Without RF its so peaceful.