Not that it will do any good, but please add my name to the list of folks requesting support for DFS. A couple notes:
First, I don't care about the Roku remote. I have a TCL Roku TV that supports an IR remote that does everything I need to do. The way I understand this thread, were it not for the Roku wifi remote, we wouldn't even need to be having this discussion.
Second, I have a BGW320-505 gateway supplied by AT&T. It does not allow users to change 5G channels. It broadcasts on two 5G channels simultaneously and occasionally it will broadcast on 2 DFS channels, at which point my TV disconnects from wifi.
My "fix" has been to switch the Roku TV over to the 2.4G band and hope that the congestion there doesn't spoil my TV viewing. Another option is to go into the BGW's interface and force it to switch 5G channels when my TV disconnects and cross my fingers hoping that it picks at least one non-DFS channel so the TV connects.
A final option is to buy a router that supports user 5G channel switching and stand it up behind the BGW. In that case, I'd be hoping to find such a router that could broadcast on two channels so that all my other clients that support DFS can run on a relatively uncongested DFS channel. (If anyone reading this knows of such a router, please advise.)
AT&T does not allow users to disable DFS channels on the BGW320-505, so, since it also will not let you choose a 5G channel (or channels), you're stuck with whatever channels the gateway chooses. Some percentage of the time, it will randomly choose two DFS channels, which causes any Roku device to disconnect.
I actually like the fact that the BGW supports DFS channels, since they tend to be way less congested than non-DFS channels. The only devices in my house that can't see a DFS channel are my two Roku TVs. All the rest of them enjoy relatively uncongested wifi channels.