I had thought that powering the Roku from an AC adapter fixed my problem, but I was wrong. I began getting the 5 seconds and then video freeze once again. I did the 5 "home" button presses and then 5 "back" button presses and got the following:
Issue Report Tracker
Moel 3941X - Roku Express 4K+
Serial number X01600YSJY6S (S07P216SJY6S)
Software version 11.5.0 - build 4235-CR
Please use issue ID 6S-456-002 to report the current issue.