The only add on devices that can decrypt the DRM channels right now are single boxes that attach directly to your TV. There is no "network tuner" device like the Flex 4k that can decrypt the DRM channels and display them on any TV or device on your network. That rules our *****, Plex, Channels or other software that makes your OTA signals work over your network. That means one box per TV is required. I think it also means you won't be able to view channels on your tablet, phone or computer.
From what I've read here, SD is working with them to make the Flex 4k work. SD has said that when the fix is complete, it will be a firmware update to our devices, and won't require new hardware.