Well got home from Dr's and checked on Roku TV, Xfinity app was still working. Came upstairs and reinstalled app on Roku 4660x2. And guess what? Dreaded death loop was still there! Then hubby called me to let me know that the xfinity app stopped working downstairs on Roku TV. So back to square one. Time to look for a streaming channels......been with comcast/xfinity since 1990.
Just an update. On the 27th of Jan (Day 7 or 8 of no xfinity) I sent Xfinity notice that if this situation was not fixed by the 31st that I was dropping xfinity. I also told them not to send message wanting me to complete all those deleting apps and resetting EVERYTHING unless they can guarantee that it would work. Of course I received a message back with a bunch of "OH we don't want to lose you...." And that they were still trying to fix the issue. Anyway come Saturday morning (29th) I decided to just check app and when I went to sign in, it went through! So then I go downstairs to check the Roku TV and low and behold it worked too! As of today 2/3/22 apps are both devices are working.
Not sure what they did to fix mine, but it is working.