Paramount+ App via Xfinity Set Top Box Painfully Slow / Buffers Regularly

The Paramount+ app playback is painfully slow and buffers (pauses playback intermittently) every time we attempt to watch. The Paramount+ app, watched via an Xfinity set top box, is the only app this occurs for. We have 1000MB Download & 100MB Upload Service and tests via Wifi confirm we are getting 800MB DL and 67MB UL, so it does not appear to be a connection problem. We have tried the following troubleshooting steps, set top box restart, modem restart, system reboot, cable tightening. This problem is unique to the Paramount+ app accessed via the Xfinity set top box (both the DVR Box and the small satellite boxes on multiple TV's). To be fair, there are other apps that are slow (Amazon, peacock, etc.) but most apps work fine and none of them pause and interrupt playback regularly like the Paramount+ app.