Technical question: firestick + xfinity flex

We moved to an area with Comcast/xfinity, which sent us a free Flex box for streaming. It's okay, but it doesn't access Apple TV+ or Kanopy, two of our favorite places. I tried unplugging the Flex box and plugging our firestick in for the first time in three months. Firestick just sat there forever saying, "Updating," with no apparent movement for, oh, 20 minutes.

Does anyone know if the Flex somehow incapacitates the TV to accept Firestick? Or do I just need to be more patient?