Sept 30, 2022 - Remedy/Workaround
Until ROKU fixes the problem with the channel guide reverting to ALL CHANNELS each time you turn off the tv or change inputs, here is a temporary fix that worked for me:
1 Launch the guide, navigate to the left-most column to highlight the actual channel, then press * for options.
2. Select MANAGE CHANNELS,
3. Select EDIT CHANNEL LINEUP
4. Place check marks in each of the channels listed that do not have a heart symbol (indicating they are favorited) or any channels that you do NOT want to see in the channel guide when you open it.
5. Yes, the channel guide has LOTS of channels to have to do this too, but the effort will save you frustration once this is complete. When done with this step and all channels, back out of everything.
Now, the next time you turn your tv on or change inputs and go back to the guide, it may say ALL CHANNELS, but the only channels that appear will be the ones you WANT to appear.
No, I don't work for ROKU, but I was equally frustated with the last guide/sofware updates and defaults.
Hope this helps many folks with a remedy.
FYI: This worked on my TCL Roku TV.