A similar problem is happening with some of the battery-operated remotes. There's another posted issue on that.
The remote for one of my 2 devices (Roku Express) suddenly started freezing within the last couple weeks. The only fix for me is restarting the Roku device. Both of my devices and remotes are identical, purchased within a couple months of each other, and they are simple remotes with no voice activation. They don't have power buttons or pairing buttons (either inside or outside the battery compartment), so there's nothing I can do using my remote to make it pair again.
One device and remote work fine so far, the other remote started freezing for no reason at all. None of the support suggestions are any use at all.
Since this problem is happening with multiple types of remotes, multiple types of Roku devices, and seems to have started for everyone within the last month or so (and with devices/remotes that most of us have owned for years with no problems), I suspect that it was a glitch caused by a Roku software update (one that didn't affect all devices & remotes, but triggered a glitch in some of them).
Roku tech support will doubtless have their own ideas and continue to supply us with their useless and obvious "fixes" to try before they just mark the issue as "solved" and go back to ignoring us. 🙄