Ours were mostly back by last night (channel numbers once again visible on most of our Roku devices, save for a few). The devices’ recoveries were staggered; figuring due to the timing on each one’s scheduled daily software updates. This morning, all were back to their happy selves. :^)
In good news: Forcing a software update might get others’ there too, if a version with the fix is available for the specific devices.
You can't really "force an update," all you can do is check for updates. If your Roku isn't already queued up for an update when you check, you're not going to get the update just because you checked. Best case, you're going to get updated a few hours early because you manually checked before the daily auto-check.
I noticed the channel numbers back today. Roku, please leave it as is. No more unnecessary "updates" please.
Hallelujah!!! The channel numbers are back. Roku, can we please keep it that way?!!!